[csharp][generichost] Add Option struct to enable better validation (#15977)

* add Option struct to enable better validation

* use kebab case

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java

@@ -40,6 +40,7 @@ import java.io.File;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.*;
+import java.util.stream.Collectors;
 
 import static org.openapitools.codegen.utils.CamelizeOption.LOWERCASE_FIRST_LETTER;
 import static org.openapitools.codegen.utils.StringUtils.camelize;
@@ -835,6 +836,9 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
                         }
                     }
 
+                    Set<CodegenParameter> referenceTypes = operation.allParams.stream().filter(p -> p.vendorExtensions.get("x-is-value-type") == null && !p.isNullable).collect(Collectors.toSet());
+                    operation.vendorExtensions.put("x-not-nullable-reference-types", referenceTypes);
+                    operation.vendorExtensions.put("x-has-not-nullable-reference-types", referenceTypes.size() > 0);
                     processOperation(operation);
                 }
             }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java

@@ -1028,6 +1028,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
         supportingFiles.add(new SupportingFile("ApiResponseEventArgs.mustache", clientPackageDir, "ApiResponseEventArgs.cs"));
         supportingFiles.add(new SupportingFile("JsonSerializerOptionsProvider.mustache", clientPackageDir, "JsonSerializerOptionsProvider.cs"));
         supportingFiles.add(new SupportingFile("CookieContainer.mustache", clientPackageDir, "CookieContainer.cs"));
+        supportingFiles.add(new SupportingFile("Option.mustache", clientPackageDir, "Option.cs"));
 
         supportingFiles.add(new SupportingFile("IApi.mustache", sourceFolder + File.separator + packageName + File.separator + apiPackage(), getInterfacePrefix() + "Api.cs"));
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/templating/mustache/TrimTrailingWhiteSpaceLambda.java

@@ -38,6 +38,6 @@ import com.samskivert.mustache.Template.Fragment;
 public class TrimTrailingWhiteSpaceLambda implements Mustache.Lambda {
     @Override
     public void execute(Fragment fragment, Writer writer) throws IOException {
-        writer.write(fragment.execute().stripTrailing());
+        writer.write(fragment.execute().stripTrailing() + "\n");
     }
 }

modules/openapi-generator/src/main/resources/csharp/NullConditionalParameter.mustache

@@ -1 +1 @@
-{{#notRequiredOrIsNullable}}{{nrt?}}{{^nrt}}{{#vendorExtensions.x-is-value-type}}?{{/vendorExtensions.x-is-value-type}}{{/nrt}}{{/notRequiredOrIsNullable}}
+{{#isNullable}}{{nrt?}}{{^nrt}}{{#vendorExtensions.x-is-value-type}}?{{/vendorExtensions.x-is-value-type}}{{/nrt}}{{/isNullable}}

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/ApiTestsBase.mustache

@@ -57,7 +57,9 @@ namespace {{packageName}}.Test.{{apiPackage}}
                 {{#hasOAuthMethods}}
                 string oauthTokenValue = context.Configuration["<token>"] ?? throw new Exception("Token not found.");
                 OAuthToken oauthToken = new{{^net70OrLater}} OAuthToken{{/net70OrLater}}(oauthTokenValue, timeout: TimeSpan.FromSeconds(1));
-                options.AddTokens(oauthToken);{{/hasOAuthMethods}}{{/lambda.trimTrailingWhiteSpace}}
+                options.AddTokens(oauthToken);
+                {{/hasOAuthMethods}}
+                {{/lambda.trimTrailingWhiteSpace}}
             });
     }
 }

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/JsonConverter.mustache

@@ -503,6 +503,16 @@
             {{^isDate}}
             {{^isDateTime}}
             writer.WritePropertyName("{{baseName}}");
-            JsonSerializer.Serialize(writer, {{#lambda.camelcase_param}}{{classname}}{{/lambda.camelcase_param}}.{{name}}, jsonSerializerOptions);{{/isDateTime}}{{/isDate}}{{/isNumeric}}{{/isBoolean}}{{/isString}}{{/isEnum}}{{/isUuid}}{{/allVars}}{{/lambda.trimLineBreaks}}{{/lambda.trimTrailingWhiteSpace}}
+            JsonSerializer.Serialize(writer, {{#lambda.camelcase_param}}{{classname}}{{/lambda.camelcase_param}}.{{name}}, jsonSerializerOptions);
+            {{/isDateTime}}
+            {{/isDate}}
+            {{/isNumeric}}
+            {{/isBoolean}}
+            {{/isString}}
+            {{/isEnum}}
+            {{/isUuid}}
+            {{/allVars}}
+            {{/lambda.trimLineBreaks}}
+            {{/lambda.trimTrailingWhiteSpace}}
         }
     }

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/OperationSignature.mustache

@@ -1 +1 @@
-{{#lambda.joinWithComma}}{{#allParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}{{#notRequiredOrIsNullable}} = null{{/notRequiredOrIsNullable}}  {{/allParams}}System.Threading.CancellationToken cancellationToken = default{{^netstandard20OrLater}}(System.Threading.CancellationToken){{/netstandard20OrLater}}{{/lambda.joinWithComma}}
+{{#lambda.joinWithComma}}{{#allParams}}{{#required}}{{{dataType}}}{{>NullConditionalParameter}}{{/required}}{{^required}}Option<{{{dataType}}}{{>NullConditionalParameter}}>{{/required}} {{paramName}}{{#notRequiredOrIsNullable}} = default{{/notRequiredOrIsNullable}}  {{/allParams}}System.Threading.CancellationToken cancellationToken = default{{^netstandard20OrLater}}(System.Threading.CancellationToken){{/netstandard20OrLater}}{{/lambda.joinWithComma}}

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/Option.mustache

@@ -0,0 +1,35 @@
+// <auto-generated>
+{{>partial_header}}
+{{#nrt}}
+#nullable enable
+
+{{/nrt}}
+
+namespace {{packageName}}.{{clientPackage}}
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api.mustache

@@ -128,53 +128,41 @@ namespace {{packageName}}.{{apiPackage}}
 
         {{#allParams}}
         {{#-first}}
-        partial void Format{{operationId}}({{#allParams}}{{#isPrimitiveType}}ref {{/isPrimitiveType}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}});
+        partial void Format{{operationId}}({{#allParams}}{{#isPrimitiveType}}ref {{/isPrimitiveType}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}});
 
         {{/-first}}
         {{/allParams}}
-        {{#notNullableParams}}
-        {{#-first}}
+        {{#vendorExtensions.x-has-not-nullable-reference-types}}
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        {{/-first}}
+        {{#vendorExtensions.x-not-nullable-reference-types}}
         /// <param name="{{paramName}}"></param>
-        {{#-last}}
+        {{/vendorExtensions.x-not-nullable-reference-types}}
         /// <returns></returns>
-        private void Validate{{operationId}}({{#notNullableParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}{{^-last}}, {{/-last}}{{/notNullableParams}})
+        private void Validate{{operationId}}({{#vendorExtensions.x-not-nullable-reference-types}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}{{^-last}}, {{/-last}}{{/vendorExtensions.x-not-nullable-reference-types}})
         {
-            {{#notNullableParams}}
-            {{#-first}}
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            {{/-first}}
-            {{#nrt}}
-            if ({{paramName}} == null)
-                throw new ArgumentNullException(nameof({{paramName}}));
-
-            {{/nrt}}
-            {{^nrt}}
+            {{#lambda.trimTrailingWhiteSpace}}
+            {{#vendorExtensions.x-not-nullable-reference-types}}
+            {{#required}}
             {{^vendorExtensions.x-is-value-type}}
             if ({{paramName}} == null)
                 throw new ArgumentNullException(nameof({{paramName}}));
 
             {{/vendorExtensions.x-is-value-type}}
-            {{#vendorExtensions.x-is-value-type}}
-            if ({{paramName}} == null)
+            {{/required}}
+            {{^required}}
+            {{^vendorExtensions.x-is-value-type}}
+            if ({{paramName}}.IsSet && {{paramName}}.Value == null)
                 throw new ArgumentNullException(nameof({{paramName}}));
 
             {{/vendorExtensions.x-is-value-type}}
-            {{/nrt}}
-            {{#-last}}
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            {{/-last}}
-            {{/notNullableParams}}
+            {{/required}}
+            {{/vendorExtensions.x-not-nullable-reference-types}}
+            {{/lambda.trimTrailingWhiteSpace}}
         }
 
-        {{/-last}}
-        {{/notNullableParams}}
+        {{/vendorExtensions.x-has-not-nullable-reference-types}}
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -182,7 +170,7 @@ namespace {{packageName}}.{{apiPackage}}
         {{#allParams}}
         /// <param name="{{paramName}}"></param>
         {{/allParams}}
-        private void After{{operationId}}DefaultImplementation({{#lambda.joinWithComma}}ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}object{{/returnType}}> apiResponseLocalVar  {{#allParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}})
+        private void After{{operationId}}DefaultImplementation({{#lambda.joinWithComma}}ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}object{{/returnType}}> apiResponseLocalVar  {{#allParams}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}})
         {
             bool suppressDefaultLog = false;
             After{{operationId}}({{#lambda.joinWithComma}}ref suppressDefaultLog  apiResponseLocalVar  {{#allParams}}{{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
@@ -197,7 +185,7 @@ namespace {{packageName}}.{{apiPackage}}
         {{#allParams}}
         /// <param name="{{paramName}}"></param>
         {{/allParams}}
-        partial void After{{operationId}}({{#lambda.joinWithComma}}ref bool suppressDefaultLog  ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}object{{/returnType}}> apiResponseLocalVar  {{#allParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
+        partial void After{{operationId}}({{#lambda.joinWithComma}}ref bool suppressDefaultLog  ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}object{{/returnType}}> apiResponseLocalVar  {{#allParams}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -208,7 +196,7 @@ namespace {{packageName}}.{{apiPackage}}
         {{#allParams}}
         /// <param name="{{paramName}}"></param>
         {{/allParams}}
-        private void OnError{{operationId}}DefaultImplementation({{#lambda.joinWithComma}}Exception exception  string pathFormat  string path  {{#allParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}})
+        private void OnError{{operationId}}DefaultImplementation({{#lambda.joinWithComma}}Exception exception  string pathFormat  string path  {{#allParams}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}})
         {
 {{>OnErrorDefaultImplementation}}
             OnError{{operationId}}({{#lambda.joinWithComma}}exception  pathFormat  path  {{#allParams}}{{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
@@ -223,7 +211,7 @@ namespace {{packageName}}.{{apiPackage}}
         {{#allParams}}
         /// <param name="{{paramName}}"></param>
         {{/allParams}}
-        partial void OnError{{operationId}}({{#lambda.joinWithComma}}Exception exception  string pathFormat  string path  {{#allParams}}{{{dataType}}}{{>NullConditionalParameter}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
+        partial void OnError{{operationId}}({{#lambda.joinWithComma}}Exception exception  string pathFormat  string path  {{#allParams}}{{^required}}Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}}  {{/allParams}}{{/lambda.joinWithComma}});
 
         /// <summary>
         /// {{summary}} {{notes}}
@@ -261,12 +249,10 @@ namespace {{packageName}}.{{apiPackage}}
 
             try
             {
-                {{#notNullableParams}}
-                {{#-first}}
-                Validate{{operationId}}({{#notNullableParams}}{{paramName}}{{^-last}}, {{/-last}}{{/notNullableParams}});
+                {{#vendorExtensions.x-has-not-nullable-reference-types}}
+                Validate{{operationId}}({{#vendorExtensions.x-not-nullable-reference-types}}{{paramName}}{{^-last}}, {{/-last}}{{/vendorExtensions.x-not-nullable-reference-types}});
 
-                {{/-first}}
-                {{/notNullableParams}}
+                {{/vendorExtensions.x-has-not-nullable-reference-types}}
                 {{#allParams}}
                 {{#-first}}
                 Format{{operationId}}({{#allParams}}{{#isPrimitiveType}}ref {{/isPrimitiveType}}{{paramName}}{{^-last}}, {{/-last}}{{/allParams}});
@@ -295,8 +281,8 @@ namespace {{packageName}}.{{apiPackage}}
                     {{/required}}
                     {{^required}}
 
-                    if ({{paramName}} != null)
-                        uriBuilderLocalVar.Path = uriBuilderLocalVar.Path + $"/{ Uri.EscapeDataString({{paramName}}).ToString()) }";
+                    if ({{paramName}}.IsSet)
+                        uriBuilderLocalVar.Path = uriBuilderLocalVar.Path + $"/{ Uri.EscapeDataString({{paramName}}.Value).ToString()) }";
                     {{#-last}}
 
                     {{/-last}}
@@ -325,14 +311,14 @@ namespace {{packageName}}.{{apiPackage}}
                     {{/-first}}
                     {{/required}}
                     {{#required}}
-                    parseQueryStringLocalVar["{{baseName}}"] = {{paramName}}.ToString();
+                    parseQueryStringLocalVar["{{baseName}}"] = {{paramName}}{{#isNullable}}{{nrt?}}{{^nrt}}{{#vendorExtensions.x-is-value-type}}?{{/vendorExtensions.x-is-value-type}}{{/nrt}}{{/isNullable}}.ToString();
                     {{/required}}
                     {{/queryParams}}
 
                     {{#queryParams}}
                     {{^required}}
-                    if ({{paramName}} != null)
-                        parseQueryStringLocalVar["{{baseName}}"] = {{paramName}}.ToString();
+                    if ({{paramName}}.IsSet)
+                        parseQueryStringLocalVar["{{baseName}}"] = {{paramName}}.Value{{#isNullable}}{{nrt?}}{{^nrt}}{{#vendorExtensions.x-is-value-type}}?{{/vendorExtensions.x-is-value-type}}{{/nrt}}{{/isNullable}}.ToString();
 
                     {{/required}}
                     {{#-last}}
@@ -346,8 +332,8 @@ namespace {{packageName}}.{{apiPackage}}
 
                     {{/required}}
                     {{^required}}
-                    if ({{paramName}} != null)
-                        httpRequestMessageLocalVar.Headers.Add("{{baseName}}", ClientUtils.ParameterToString({{paramName}}));
+                    if ({{paramName}}.IsSet)
+                        httpRequestMessageLocalVar.Headers.Add("{{baseName}}", ClientUtils.ParameterToString({{paramName}}.Value));
 
                     {{/required}}
                     {{/headerParams}}
@@ -365,8 +351,8 @@ namespace {{packageName}}.{{apiPackage}}
 
                     {{/required}}
                     {{^required}}
-                    if ({{paramName}} != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string{{nrt?}}, string{{nrt?}}>("{{baseName}}", ClientUtils.ParameterToString({{paramName}})));
+                    if ({{paramName}}.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string{{nrt?}}, string{{nrt?}}>("{{baseName}}", ClientUtils.ParameterToString({{paramName}}.Value)));
 
                     {{/required}}
                     {{/isFile}}
@@ -376,16 +362,24 @@ namespace {{packageName}}.{{apiPackage}}
 
                     {{/required}}
                     {{^required}}
-                    if ({{paramName}} != null)
-                        multipartContentLocalVar.Add(new StreamContent({{paramName}}));
+                    if ({{paramName}}.IsSet)
+                        multipartContentLocalVar.Add(new StreamContent({{paramName}}.Value));
 
                     {{/required}}
                     {{/isFile}}
                     {{/formParams}}
                     {{#bodyParam}}
-                    httpRequestMessageLocalVar.Content = ({{paramName}} as object) is System.IO.Stream stream
+                    {{#required}}
+                    httpRequestMessageLocalVar.Content = ({{paramName}}{{^required}}.Value{{/required}} as object) is System.IO.Stream stream
                         ? httpRequestMessageLocalVar.Content = new StreamContent(stream)
-                        : httpRequestMessageLocalVar.Content = new StringContent(JsonSerializer.Serialize({{paramName}}, _jsonSerializerOptions));
+                        : httpRequestMessageLocalVar.Content = new StringContent(JsonSerializer.Serialize({{paramName}}{{^required}}.Value{{/required}}, _jsonSerializerOptions));
+                    {{/required}}
+                    {{^required}}
+                    if ({{paramName}}.IsSet)
+                        httpRequestMessageLocalVar.Content = ({{paramName}}{{^required}}.Value{{/required}} as object) is System.IO.Stream stream
+                            ? httpRequestMessageLocalVar.Content = new StreamContent(stream)
+                            : httpRequestMessageLocalVar.Content = new StringContent(JsonSerializer.Serialize({{paramName}}{{^required}}.Value{{/required}}, _jsonSerializerOptions));
+                    {{/required}}
 
                     {{/bodyParam}}
                     {{#authMethods}}
@@ -442,9 +436,11 @@ namespace {{packageName}}.{{apiPackage}}
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content{{nrt!}}.ReadAsStringAsync({{#net60OrLater}}cancellationToken{{/net60OrLater}}).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync({{#net60OrLater}}cancellationToken{{/net60OrLater}}).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
                     {{/isHttpSignature}}
                     {{/authMethods}}
                     {{#consumes}}
@@ -462,7 +458,7 @@ namespace {{packageName}}.{{apiPackage}}
 
                     string{{nrt?}} contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     {{/-first}}

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/api_test.mustache

@@ -34,7 +34,7 @@ namespace {{packageName}}.Test.{{apiPackage}}
         public async Task {{operationId}}AsyncTest()
         {
             {{#allParams}}
-            {{{dataType}}} {{paramName}} = default{{nrt!}};
+            {{^required}}Client.Option<{{/required}}{{{dataType}}}{{>NullConditionalParameter}}{{^required}}>{{/required}} {{paramName}} = default{{nrt!}};
             {{/allParams}}
             {{#returnType}}
             var response = await _instance.{{operationId}}Async({{#allParams}}{{paramName}}{{^-last}}, {{/-last}}{{/allParams}});

modules/openapi-generator/src/main/resources/csharp/model_test.mustache

@@ -77,7 +77,10 @@ namespace {{packageName}}.Test.Model
         public void {{name}}Test()
         {
             // TODO unit test for the property '{{name}}'
-        }{{/vars}}{{/lambda.trimLineBreaks}}{{/lambda.trimTrailingWhiteSpace}}
+        }
+        {{/vars}}
+        {{/lambda.trimLineBreaks}}
+        {{/lambda.trimTrailingWhiteSpace}}
     }
 }
 {{/model}}

modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml

@@ -1067,6 +1067,34 @@ paths:
             type: array
             items:
               type: string
+        - name: requiredNotNullable
+          in: query
+          required: true
+          explode: true
+          schema:
+            type: string
+            nullable: false
+        - name: requiredNullable
+          in: query
+          required: true
+          explode: true
+          schema:
+            type: string
+            nullable: true
+        - name: notRequiredNotNullable
+          in: query
+          required: false
+          explode: true
+          schema:
+            type: string
+            nullable: false
+        - name: notRequiredNullable
+          in: query
+          required: false
+          explode: true
+          schema:
+            type: string
+            nullable: true
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-ConditionalSerialization/api/openapi.yaml

@@ -1036,6 +1036,38 @@ paths:
             type: string
           type: array
         style: form
+      - explode: true
+        in: query
+        name: requiredNotNullable
+        required: true
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: requiredNullable
+        required: true
+        schema:
+          nullable: true
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNotNullable
+        required: false
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNullable
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: form
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-ConditionalSerialization/docs/FakeApi.md

@@ -1301,7 +1301,7 @@ No authorization required
 
 <a id="testqueryparametercollectionformat"></a>
 # **TestQueryParameterCollectionFormat**
-> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context)
+> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = null, string notRequiredNullable = null)
 
 
 
@@ -1329,10 +1329,14 @@ namespace Example
             var http = new List<string>(); // List<string> | 
             var url = new List<string>(); // List<string> | 
             var context = new List<string>(); // List<string> | 
+            var requiredNotNullable = "requiredNotNullable_example";  // string | 
+            var requiredNullable = "requiredNullable_example";  // string | 
+            var notRequiredNotNullable = "notRequiredNotNullable_example";  // string |  (optional) 
+            var notRequiredNullable = "notRequiredNullable_example";  // string |  (optional) 
 
             try
             {
-                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
+                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
             }
             catch (ApiException  e)
             {
@@ -1351,7 +1355,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
 }
 catch (ApiException e)
 {
@@ -1370,6 +1374,10 @@ catch (ApiException e)
 | **http** | [**List&lt;string&gt;**](string.md) |  |  |
 | **url** | [**List&lt;string&gt;**](string.md) |  |  |
 | **context** | [**List&lt;string&gt;**](string.md) |  |  |
+| **requiredNotNullable** | **string** |  |  |
+| **requiredNullable** | **string** |  |  |
+| **notRequiredNotNullable** | **string** |  | [optional]  |
+| **notRequiredNullable** | **string** |  | [optional]  |
 
 ### Return type
 

samples/client/petstore/csharp/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -398,9 +398,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns></returns>
-        void TestQueryParameterCollectionFormat(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0);
+        void TestQueryParameterCollectionFormat(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -414,9 +418,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of Object(void)</returns>
-        ApiResponse<Object> TestQueryParameterCollectionFormatWithHttpInfo(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0);
+        ApiResponse<Object> TestQueryParameterCollectionFormatWithHttpInfo(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0);
         #endregion Synchronous Operations
     }
 
@@ -840,10 +848,14 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of void</returns>
-        System.Threading.Tasks.Task TestQueryParameterCollectionFormatAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task TestQueryParameterCollectionFormatAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -857,10 +869,14 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse</returns>
-        System.Threading.Tasks.Task<ApiResponse<Object>> TestQueryParameterCollectionFormatWithHttpInfoAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<Object>> TestQueryParameterCollectionFormatWithHttpInfoAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         #endregion Asynchronous Operations
     }
 
@@ -3246,11 +3262,15 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns></returns>
-        public void TestQueryParameterCollectionFormat(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0)
+        public void TestQueryParameterCollectionFormat(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0)
         {
-            TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+            TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
         }
 
         /// <summary>
@@ -3262,9 +3282,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of Object(void)</returns>
-        public Org.OpenAPITools.Client.ApiResponse<Object> TestQueryParameterCollectionFormatWithHttpInfo(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<Object> TestQueryParameterCollectionFormatWithHttpInfo(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0)
         {
             // verify the required parameter 'pipe' is set
             if (pipe == null)
@@ -3296,6 +3320,18 @@ namespace Org.OpenAPITools.Api
                 throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'context' when calling FakeApi->TestQueryParameterCollectionFormat");
             }
 
+            // verify the required parameter 'requiredNotNullable' is set
+            if (requiredNotNullable == null)
+            {
+                throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'requiredNotNullable' when calling FakeApi->TestQueryParameterCollectionFormat");
+            }
+
+            // verify the required parameter 'requiredNullable' is set
+            if (requiredNullable == null)
+            {
+                throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'requiredNullable' when calling FakeApi->TestQueryParameterCollectionFormat");
+            }
+
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
             string[] _contentTypes = new string[] {
@@ -3322,6 +3358,16 @@ namespace Org.OpenAPITools.Api
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("ssv", "http", http));
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("csv", "url", url));
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("multi", "context", context));
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "requiredNotNullable", requiredNotNullable));
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "requiredNullable", requiredNullable));
+            if (notRequiredNotNullable != null)
+            {
+                localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "notRequiredNotNullable", notRequiredNotNullable));
+            }
+            if (notRequiredNullable != null)
+            {
+                localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "notRequiredNullable", notRequiredNullable));
+            }
 
             localVarRequestOptions.Operation = "FakeApi.TestQueryParameterCollectionFormat";
             localVarRequestOptions.OperationIndex = operationIndex;
@@ -3350,12 +3396,16 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of void</returns>
-        public async System.Threading.Tasks.Task TestQueryParameterCollectionFormatAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task TestQueryParameterCollectionFormatAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            await TestQueryParameterCollectionFormatWithHttpInfoAsync(pipe, ioutil, http, url, context, operationIndex, cancellationToken).ConfigureAwait(false);
+            await TestQueryParameterCollectionFormatWithHttpInfoAsync(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable, operationIndex, cancellationToken).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -3367,10 +3417,14 @@ namespace Org.OpenAPITools.Api
         /// <param name="http"></param>
         /// <param name="url"></param>
         /// <param name="context"></param>
+        /// <param name="requiredNotNullable"></param>
+        /// <param name="requiredNullable"></param>
+        /// <param name="notRequiredNotNullable"> (optional)</param>
+        /// <param name="notRequiredNullable"> (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<Object>> TestQueryParameterCollectionFormatWithHttpInfoAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<Object>> TestQueryParameterCollectionFormatWithHttpInfoAsync(List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = default(string), string notRequiredNullable = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
             // verify the required parameter 'pipe' is set
             if (pipe == null)
@@ -3402,6 +3456,18 @@ namespace Org.OpenAPITools.Api
                 throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'context' when calling FakeApi->TestQueryParameterCollectionFormat");
             }
 
+            // verify the required parameter 'requiredNotNullable' is set
+            if (requiredNotNullable == null)
+            {
+                throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'requiredNotNullable' when calling FakeApi->TestQueryParameterCollectionFormat");
+            }
+
+            // verify the required parameter 'requiredNullable' is set
+            if (requiredNullable == null)
+            {
+                throw new Org.OpenAPITools.Client.ApiException(400, "Missing required parameter 'requiredNullable' when calling FakeApi->TestQueryParameterCollectionFormat");
+            }
+
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -3429,6 +3495,16 @@ namespace Org.OpenAPITools.Api
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("ssv", "http", http));
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("csv", "url", url));
             localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("multi", "context", context));
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "requiredNotNullable", requiredNotNullable));
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "requiredNullable", requiredNullable));
+            if (notRequiredNotNullable != null)
+            {
+                localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "notRequiredNotNullable", notRequiredNotNullable));
+            }
+            if (notRequiredNullable != null)
+            {
+                localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "notRequiredNullable", notRequiredNullable));
+            }
 
             localVarRequestOptions.Operation = "FakeApi.TestQueryParameterCollectionFormat";
             localVarRequestOptions.OperationIndex = operationIndex;

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/.openapi-generator/FILES

@@ -123,6 +123,7 @@ src/Org.OpenAPITools/Client/HttpSigningConfiguration.cs
 src/Org.OpenAPITools/Client/HttpSigningToken.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
 src/Org.OpenAPITools/Client/OAuthToken.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/api/openapi.yaml

@@ -1036,6 +1036,38 @@ paths:
             type: string
           type: array
         style: form
+      - explode: true
+        in: query
+        name: requiredNotNullable
+        required: true
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: requiredNullable
+        required: true
+        schema:
+          nullable: true
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNotNullable
+        required: false
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNullable
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: form
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/docs/apis/FakeApi.md

@@ -1301,7 +1301,7 @@ No authorization required
 
 <a id="testqueryparametercollectionformat"></a>
 # **TestQueryParameterCollectionFormat**
-> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context)
+> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = null, string notRequiredNullable = null)
 
 
 
@@ -1329,10 +1329,14 @@ namespace Example
             var http = new List<string>(); // List<string> | 
             var url = new List<string>(); // List<string> | 
             var context = new List<string>(); // List<string> | 
+            var requiredNotNullable = "requiredNotNullable_example";  // string | 
+            var requiredNullable = "requiredNullable_example";  // string | 
+            var notRequiredNotNullable = "notRequiredNotNullable_example";  // string |  (optional) 
+            var notRequiredNullable = "notRequiredNullable_example";  // string |  (optional) 
 
             try
             {
-                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
+                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
             }
             catch (ApiException  e)
             {
@@ -1351,7 +1355,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
 }
 catch (ApiException e)
 {
@@ -1370,6 +1374,10 @@ catch (ApiException e)
 | **http** | [**List&lt;string&gt;**](string.md) |  |  |
 | **url** | [**List&lt;string&gt;**](string.md) |  |  |
 | **context** | [**List&lt;string&gt;**](string.md) |  |  |
+| **requiredNotNullable** | **string** |  |  |
+| **requiredNullable** | **string** |  |  |
+| **notRequiredNotNullable** | **string** |  | [optional]  |
+| **notRequiredNullable** | **string** |  | [optional]  |
 
 ### Return type
 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterBooleanSerializeAsyncTest()
         {
-            bool body = default!;
+            Client.Option<bool> body = default!;
             var response = await _instance.FakeOuterBooleanSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<bool>(model);
@@ -79,7 +79,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterCompositeSerializeAsyncTest()
         {
-            OuterComposite outerComposite = default!;
+            Client.Option<OuterComposite> outerComposite = default!;
             var response = await _instance.FakeOuterCompositeSerializeAsync(outerComposite);
             var model = response.AsModel();
             Assert.IsType<OuterComposite>(model);
@@ -91,7 +91,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterNumberSerializeAsyncTest()
         {
-            decimal body = default!;
+            Client.Option<decimal> body = default!;
             var response = await _instance.FakeOuterNumberSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<decimal>(model);
@@ -104,7 +104,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task FakeOuterStringSerializeAsyncTest()
         {
             Guid requiredStringUuid = default!;
-            string body = default!;
+            Client.Option<string> body = default!;
             var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             var model = response.AsModel();
             Assert.IsType<string>(model);
@@ -164,16 +164,16 @@ namespace Org.OpenAPITools.Test.Api
             decimal number = default!;
             double varDouble = default!;
             string patternWithoutDelimiter = default!;
-            DateTime date = default!;
-            System.IO.Stream binary = default!;
-            float varFloat = default!;
-            int integer = default!;
-            int int32 = default!;
-            long int64 = default!;
-            string varString = default!;
-            string password = default!;
-            string callback = default!;
-            DateTime dateTime = default!;
+            Client.Option<DateTime> date = default!;
+            Client.Option<System.IO.Stream> binary = default!;
+            Client.Option<float> varFloat = default!;
+            Client.Option<int> integer = default!;
+            Client.Option<int> int32 = default!;
+            Client.Option<long> int64 = default!;
+            Client.Option<string> varString = default!;
+            Client.Option<string> password = default!;
+            Client.Option<string> callback = default!;
+            Client.Option<DateTime> dateTime = default!;
             await _instance.TestEndpointParametersAsync(varByte, number, varDouble, patternWithoutDelimiter, date, binary, varFloat, integer, int32, int64, varString, password, callback, dateTime);
         }
 
@@ -183,14 +183,14 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task TestEnumParametersAsyncTest()
         {
-            List<string> enumHeaderStringArray = default!;
-            List<string> enumQueryStringArray = default!;
-            double enumQueryDouble = default!;
-            int enumQueryInteger = default!;
-            List<string> enumFormStringArray = default!;
-            string enumHeaderString = default!;
-            string enumQueryString = default!;
-            string enumFormString = default!;
+            Client.Option<List<string>> enumHeaderStringArray = default!;
+            Client.Option<List<string>> enumQueryStringArray = default!;
+            Client.Option<double> enumQueryDouble = default!;
+            Client.Option<int> enumQueryInteger = default!;
+            Client.Option<List<string>> enumFormStringArray = default!;
+            Client.Option<string> enumHeaderString = default!;
+            Client.Option<string> enumQueryString = default!;
+            Client.Option<string> enumFormString = default!;
             await _instance.TestEnumParametersAsync(enumHeaderStringArray, enumQueryStringArray, enumQueryDouble, enumQueryInteger, enumFormStringArray, enumHeaderString, enumQueryString, enumFormString);
         }
 
@@ -203,9 +203,9 @@ namespace Org.OpenAPITools.Test.Api
             bool requiredBooleanGroup = default!;
             int requiredStringGroup = default!;
             long requiredInt64Group = default!;
-            bool booleanGroup = default!;
-            int stringGroup = default!;
-            long int64Group = default!;
+            Client.Option<bool> booleanGroup = default!;
+            Client.Option<int> stringGroup = default!;
+            Client.Option<long> int64Group = default!;
             await _instance.TestGroupParametersAsync(requiredBooleanGroup, requiredStringGroup, requiredInt64Group, booleanGroup, stringGroup, int64Group);
         }
 
@@ -241,7 +241,11 @@ namespace Org.OpenAPITools.Test.Api
             List<string> http = default!;
             List<string> url = default!;
             List<string> context = default!;
-            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context);
+            string requiredNotNullable = default!;
+            string? requiredNullable = default!;
+            Client.Option<string> notRequiredNotNullable = default!;
+            Client.Option<string?> notRequiredNullable = default!;
+            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/PetApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task DeletePetAsyncTest()
         {
             long petId = default!;
-            string apiKey = default!;
+            Client.Option<string> apiKey = default!;
             await _instance.DeletePetAsync(petId, apiKey);
         }
 
@@ -124,8 +124,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UpdatePetWithFormAsyncTest()
         {
             long petId = default!;
-            string name = default!;
-            string status = default!;
+            Client.Option<string> name = default!;
+            Client.Option<string> status = default!;
             await _instance.UpdatePetWithFormAsync(petId, name, status);
         }
 
@@ -136,8 +136,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UploadFileAsyncTest()
         {
             long petId = default!;
-            System.IO.Stream file = default!;
-            string additionalMetadata = default!;
+            Client.Option<System.IO.Stream> file = default!;
+            Client.Option<string> additionalMetadata = default!;
             var response = await _instance.UploadFileAsync(petId, file, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);
@@ -151,7 +151,7 @@ namespace Org.OpenAPITools.Test.Api
         {
             System.IO.Stream requiredFile = default!;
             long petId = default!;
-            string additionalMetadata = default!;
+            Client.Option<string> additionalMetadata = default!;
             var response = await _instance.UploadFileWithRequiredFileAsync(requiredFile, petId, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/AnotherFakeApi.cs

@@ -128,14 +128,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCall123TestSpecialTags(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -235,7 +229,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/DefaultApi.cs

@@ -279,14 +279,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetCountry(string country)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (country == null)
                 throw new ArgumentNullException(nameof(country));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -392,7 +386,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeClassnameTags123Api.cs

@@ -128,14 +128,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateTestClassname(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -246,7 +240,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/PetApi.cs

@@ -63,7 +63,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> DeletePetAsync(long petId, string? apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Deletes a pet
@@ -75,7 +75,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;?&gt;</returns>
-        Task<ApiResponse<object>?> DeletePetOrDefaultAsync(long petId, string? apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>?> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Finds Pets by status
@@ -181,7 +181,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string? name = null, string? status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Updates a pet in the store with form data
@@ -194,7 +194,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;?&gt;</returns>
-        Task<ApiResponse<object>?> UpdatePetWithFormOrDefaultAsync(long petId, string? name = null, string? status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>?> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -208,7 +208,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream? file = null, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -221,7 +221,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;?&gt;</returns>
-        Task<ApiResponse<ApiResponse>?> UploadFileOrDefaultAsync(long petId, System.IO.Stream? file = null, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>?> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -235,7 +235,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -248,7 +248,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;?&gt;</returns>
-        Task<ApiResponse<ApiResponse>?> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>?> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
     }
 }
 
@@ -326,14 +326,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateAddPet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -439,9 +433,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content!.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -450,7 +446,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -484,27 +480,17 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatDeletePet(ref long petId, ref string? apiKey);
+        partial void FormatDeletePet(ref long petId, ref Option<string> apiKey);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="apiKey"></param>
         /// <returns></returns>
-        private void ValidateDeletePet(long petId, string? apiKey)
+        private void ValidateDeletePet(Option<string> apiKey)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (apiKey == null)
+            if (apiKey.IsSet && apiKey.Value == null)
                 throw new ArgumentNullException(nameof(apiKey));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -513,7 +499,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string? apiKey)
+        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey)
         {
             bool suppressDefaultLog = false;
             AfterDeletePet(ref suppressDefaultLog, apiResponseLocalVar, petId, apiKey);
@@ -528,7 +514,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string? apiKey);
+        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -538,7 +524,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string? apiKey)
+        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorDeletePet(exception, pathFormat, path, petId, apiKey);
@@ -552,7 +538,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, string? apiKey);
+        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Deletes a pet 
@@ -561,7 +547,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>?> DeletePetOrDefaultAsync(long petId, string? apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>?> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -581,13 +567,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> DeletePetAsync(long petId, string? apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateDeletePet(petId, apiKey);
+                ValidateDeletePet(apiKey);
 
                 FormatDeletePet(ref petId, ref apiKey);
 
@@ -599,8 +585,8 @@ namespace Org.OpenAPITools.Api
                     uriBuilderLocalVar.Path = ClientUtils.CONTEXT_PATH + "/pet/{petId}";
                     uriBuilderLocalVar.Path = uriBuilderLocalVar.Path.Replace("%7BpetId%7D", Uri.EscapeDataString(petId.ToString()));
 
-                    if (apiKey != null)
-                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey));
+                    if (apiKey.IsSet)
+                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey.Value));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -648,14 +634,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByStatus(List<string> status)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (status == null)
                 throw new ArgumentNullException(nameof(status));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -763,9 +743,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content!.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -817,14 +799,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByTags(List<string> tags)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (tags == null)
                 throw new ArgumentNullException(nameof(tags));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -932,9 +908,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content!.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -979,23 +957,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetPetById(ref long petId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="petId"></param>
-        /// <returns></returns>
-        private void ValidateGetPetById(long petId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -1070,8 +1031,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetPetById(petId);
-
                 FormatGetPetById(ref petId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -1138,14 +1097,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateUpdatePet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1251,9 +1204,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content!.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -1262,7 +1217,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Put;
@@ -1296,31 +1251,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUpdatePetWithForm(ref long petId, ref string? name, ref string? status);
+        partial void FormatUpdatePetWithForm(ref long petId, ref Option<string> name, ref Option<string> status);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
         /// <returns></returns>
-        private void ValidateUpdatePetWithForm(long petId, string? name, string? status)
+        private void ValidateUpdatePetWithForm(Option<string> name, Option<string> status)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (name == null)
+            if (name.IsSet && name.Value == null)
                 throw new ArgumentNullException(nameof(name));
 
-            if (status == null)
+            if (status.IsSet && status.Value == null)
                 throw new ArgumentNullException(nameof(status));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1330,7 +1275,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string? name, string? status)
+        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status)
         {
             bool suppressDefaultLog = false;
             AfterUpdatePetWithForm(ref suppressDefaultLog, apiResponseLocalVar, petId, name, status);
@@ -1346,7 +1291,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string? name, string? status);
+        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1357,7 +1302,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string? name, string? status)
+        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUpdatePetWithForm(exception, pathFormat, path, petId, name, status);
@@ -1372,7 +1317,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, string? name, string? status);
+        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Updates a pet in the store with form data 
@@ -1382,7 +1327,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>?> UpdatePetWithFormOrDefaultAsync(long petId, string? name = null, string? status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>?> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1403,13 +1348,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string? name = null, string? status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUpdatePetWithForm(petId, name, status);
+                ValidateUpdatePetWithForm(name, status);
 
                 FormatUpdatePetWithForm(ref petId, ref name, ref status);
 
@@ -1427,11 +1372,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string?, string?>> formParameterLocalVars = new List<KeyValuePair<string?, string?>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("name", ClientUtils.ParameterToString(name)));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("name", ClientUtils.ParameterToString(name.Value)));
 
-                    if (status != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("status", ClientUtils.ParameterToString(status)));
+                    if (status.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("status", ClientUtils.ParameterToString(status.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1449,7 +1394,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -1479,31 +1424,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFile(ref long petId, ref System.IO.Stream? file, ref string? additionalMetadata);
+        partial void FormatUploadFile(ref long petId, ref Option<System.IO.Stream> file, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
-        /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
+        /// <param name="file"></param>
         /// <returns></returns>
-        private void ValidateUploadFile(long petId, System.IO.Stream? file, string? additionalMetadata)
+        private void ValidateUploadFile(Option<string> additionalMetadata, Option<System.IO.Stream> file)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (file == null)
-                throw new ArgumentNullException(nameof(file));
-
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
 
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            if (file.IsSet && file.Value == null)
+                throw new ArgumentNullException(nameof(file));
         }
 
         /// <summary>
@@ -1513,7 +1448,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream? file, string? additionalMetadata)
+        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFile(ref suppressDefaultLog, apiResponseLocalVar, petId, file, additionalMetadata);
@@ -1529,7 +1464,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream? file, string? additionalMetadata);
+        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1540,7 +1475,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, System.IO.Stream? file, string? additionalMetadata)
+        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFile(exception, pathFormat, path, petId, file, additionalMetadata);
@@ -1555,7 +1490,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, System.IO.Stream? file, string? additionalMetadata);
+        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image 
@@ -1565,7 +1500,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>?> UploadFileOrDefaultAsync(long petId, System.IO.Stream? file = null, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>?> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1586,13 +1521,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream? file = null, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFile(petId, file, additionalMetadata);
+                ValidateUploadFile(additionalMetadata, file);
 
                 FormatUploadFile(ref petId, ref file, ref additionalMetadata);
 
@@ -1610,11 +1545,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string?, string?>> formParameterLocalVars = new List<KeyValuePair<string?, string?>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file != null)
-                        multipartContentLocalVar.Add(new StreamContent(file));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file.IsSet)
+                        multipartContentLocalVar.Add(new StreamContent(file.Value));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1632,7 +1567,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {
@@ -1671,31 +1606,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref string? additionalMetadata);
+        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
         /// <param name="requiredFile"></param>
-        /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
         /// <returns></returns>
-        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, long petId, string? additionalMetadata)
+        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, Option<string> additionalMetadata)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (requiredFile == null)
                 throw new ArgumentNullException(nameof(requiredFile));
 
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1705,7 +1630,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string? additionalMetadata)
+        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFileWithRequiredFile(ref suppressDefaultLog, apiResponseLocalVar, requiredFile, petId, additionalMetadata);
@@ -1721,7 +1646,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string? additionalMetadata);
+        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1732,7 +1657,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string? additionalMetadata)
+        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFileWithRequiredFile(exception, pathFormat, path, requiredFile, petId, additionalMetadata);
@@ -1747,7 +1672,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string? additionalMetadata);
+        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image (required) 
@@ -1757,7 +1682,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>?> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>?> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1778,13 +1703,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string? additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFileWithRequiredFile(requiredFile, petId, additionalMetadata);
+                ValidateUploadFileWithRequiredFile(requiredFile, additionalMetadata);
 
                 FormatUploadFileWithRequiredFile(ref requiredFile, ref petId, ref additionalMetadata);
 
@@ -1804,8 +1729,8 @@ namespace Org.OpenAPITools.Api
 
                     multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    multipartContentLocalVar.Add(new StreamContent(requiredFile));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string?, string?>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1823,7 +1748,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/StoreApi.cs

@@ -195,14 +195,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteOrder(string orderId)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (orderId == null)
                 throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -439,23 +433,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetOrderById(ref long orderId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="orderId"></param>
-        /// <returns></returns>
-        private void ValidateGetOrderById(long orderId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (orderId == null)
-                throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -530,8 +507,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetOrderById(orderId);
-
                 FormatGetOrderById(ref orderId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -586,14 +561,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidatePlaceOrder(Order order)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (order == null)
                 throw new ArgumentNullException(nameof(order));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -693,7 +662,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/UserApi.cs

@@ -291,14 +291,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUser(User user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -398,7 +392,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -433,14 +427,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithArrayInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -540,7 +528,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -575,14 +563,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithListInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -682,7 +664,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -717,14 +699,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteUser(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -847,14 +823,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetUserByName(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -988,17 +958,11 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateLoginUser(string username, string password)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
 
             if (password == null)
                 throw new ArgumentNullException(nameof(password));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1244,17 +1208,11 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateUpdateUser(User user, string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
 
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1361,7 +1319,7 @@ namespace Org.OpenAPITools.Api
 
                     string? contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Put;

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,41 @@
+// <auto-generated>
+/*
+ * OpenAPI Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+#nullable enable
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/AdditionalPropertiesClass.cs

@@ -277,13 +277,20 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, AdditionalPropertiesClass additionalPropertiesClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("empty_map");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);            writer.WritePropertyName("map_of_map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_string");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);            writer.WritePropertyName("anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_string");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);
+            writer.WritePropertyName("anytype_1");
             JsonSerializer.Serialize(writer, additionalPropertiesClass.Anytype1, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/ArrayTest.cs

@@ -194,8 +194,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ArrayTest arrayTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_array_of_integer");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);            writer.WritePropertyName("array_array_of_model");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);            writer.WritePropertyName("array_of_string");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);
+            writer.WritePropertyName("array_array_of_model");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);
+            writer.WritePropertyName("array_of_string");
             JsonSerializer.Serialize(writer, arrayTest.ArrayOfString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/Drawing.cs

@@ -199,9 +199,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Drawing drawing, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("mainShape");
-            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);            writer.WritePropertyName("shapes");
-            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);            writer.WritePropertyName("nullableShape");
-            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);            writer.WritePropertyName("shapeOrNull");
+            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapes");
+            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);
+            writer.WritePropertyName("nullableShape");
+            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapeOrNull");
             JsonSerializer.Serialize(writer, drawing.ShapeOrNull, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/EnumArrays.cs

@@ -312,6 +312,7 @@ namespace Org.OpenAPITools.Model
         {
             writer.WritePropertyName("array_enum");
             JsonSerializer.Serialize(writer, enumArrays.ArrayEnum, jsonSerializerOptions);
+
             var justSymbolRawValue = EnumArrays.JustSymbolEnumToJsonValue(enumArrays.JustSymbol);
             if (justSymbolRawValue != null)
                 writer.WriteString("just_symbol", justSymbolRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/FileSchemaTestClass.cs

@@ -177,7 +177,8 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FileSchemaTestClass fileSchemaTestClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("file");
-            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);            writer.WritePropertyName("files");
+            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);
+            writer.WritePropertyName("files");
             JsonSerializer.Serialize(writer, fileSchemaTestClass.Files, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/FormatTest.cs

@@ -589,11 +589,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FormatTest formatTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("binary");
-            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);            writer.WritePropertyName("byte");
-            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
+            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);
+            writer.WritePropertyName("byte");
+            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);
+            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
             writer.WriteString("dateTime", formatTest.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("decimal");
-            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);            writer.WriteNumber("double", formatTest.VarDouble);
+            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);
+            writer.WriteNumber("double", formatTest.VarDouble);
             writer.WriteNumber("float", formatTest.VarFloat);
             writer.WriteNumber("int32", formatTest.Int32);
             writer.WriteNumber("int64", formatTest.Int64);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MapTest.cs

@@ -277,9 +277,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, MapTest mapTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("direct_map");
-            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);            writer.WritePropertyName("indirect_map");
-            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);            writer.WritePropertyName("map_map_of_string");
-            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);            writer.WritePropertyName("map_of_enum_string");
+            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("indirect_map");
+            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_map_of_string");
+            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_enum_string");
             JsonSerializer.Serialize(writer, mapTest.MapOfEnumString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs

@@ -224,7 +224,8 @@ namespace Org.OpenAPITools.Model
         {
             writer.WriteString("dateTime", mixedPropertiesAndAdditionalPropertiesClass.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("map");
-            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
+            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
             writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/NullableClass.cs

@@ -320,10 +320,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, NullableClass nullableClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("object_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("array_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("array_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("object_items_nullable");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("array_and_items_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("array_nullable_prop");
             JsonSerializer.Serialize(writer, nullableClass.ArrayNullableProp, jsonSerializerOptions);
+
             if (nullableClass.BooleanProp != null)
                 writer.WriteBoolean("boolean_prop", nullableClass.BooleanProp.Value);
             else
@@ -350,8 +354,10 @@ namespace Org.OpenAPITools.Model
                 writer.WriteNull("number_prop");
 
             writer.WritePropertyName("object_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("object_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);            writer.WriteString("string_prop", nullableClass.StringProp);
+            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("object_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);
+            writer.WriteString("string_prop", nullableClass.StringProp);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs

@@ -213,8 +213,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ObjectWithDeprecatedFields objectWithDeprecatedFields, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("bars");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);            writer.WritePropertyName("deprecatedRef");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);
+            writer.WritePropertyName("deprecatedRef");
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);
+            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
             writer.WriteString("uuid", objectWithDeprecatedFields.Uuid);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/Pet.cs

@@ -329,10 +329,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Pet pet, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("category");
-            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);            writer.WriteNumber("id", pet.Id);
+            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);
+            writer.WriteNumber("id", pet.Id);
             writer.WriteString("name", pet.Name);
             writer.WritePropertyName("photoUrls");
             JsonSerializer.Serialize(writer, pet.PhotoUrls, jsonSerializerOptions);
+
             var statusRawValue = Pet.StatusEnumToJsonValue(pet.Status);
             if (statusRawValue != null)
                 writer.WriteString("status", statusRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/User.cs

@@ -341,13 +341,16 @@ namespace Org.OpenAPITools.Model
             writer.WriteNumber("id", user.Id);
             writer.WriteString("lastName", user.LastName);
             writer.WritePropertyName("objectWithNoDeclaredProps");
-            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);            writer.WriteString("password", user.Password);
+            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);
+            writer.WriteString("password", user.Password);
             writer.WriteString("phone", user.Phone);
             writer.WriteNumber("userStatus", user.UserStatus);
             writer.WriteString("username", user.Username);
             writer.WritePropertyName("anyTypeProp");
-            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);            writer.WritePropertyName("anyTypePropNullable");
-            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);
+            writer.WritePropertyName("anyTypePropNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);
+            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
             JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredPropsNullable, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/.openapi-generator/FILES

@@ -123,6 +123,7 @@ src/Org.OpenAPITools/Client/HttpSigningConfiguration.cs
 src/Org.OpenAPITools/Client/HttpSigningToken.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
 src/Org.OpenAPITools/Client/OAuthToken.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/api/openapi.yaml

@@ -1036,6 +1036,38 @@ paths:
             type: string
           type: array
         style: form
+      - explode: true
+        in: query
+        name: requiredNotNullable
+        required: true
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: requiredNullable
+        required: true
+        schema:
+          nullable: true
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNotNullable
+        required: false
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNullable
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: form
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/docs/apis/FakeApi.md

@@ -1301,7 +1301,7 @@ No authorization required
 
 <a id="testqueryparametercollectionformat"></a>
 # **TestQueryParameterCollectionFormat**
-> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context)
+> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = null, string notRequiredNullable = null)
 
 
 
@@ -1329,10 +1329,14 @@ namespace Example
             var http = new List<string>(); // List<string> | 
             var url = new List<string>(); // List<string> | 
             var context = new List<string>(); // List<string> | 
+            var requiredNotNullable = "requiredNotNullable_example";  // string | 
+            var requiredNullable = "requiredNullable_example";  // string | 
+            var notRequiredNotNullable = "notRequiredNotNullable_example";  // string |  (optional) 
+            var notRequiredNullable = "notRequiredNullable_example";  // string |  (optional) 
 
             try
             {
-                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
+                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
             }
             catch (ApiException  e)
             {
@@ -1351,7 +1355,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
 }
 catch (ApiException e)
 {
@@ -1370,6 +1374,10 @@ catch (ApiException e)
 | **http** | [**List&lt;string&gt;**](string.md) |  |  |
 | **url** | [**List&lt;string&gt;**](string.md) |  |  |
 | **context** | [**List&lt;string&gt;**](string.md) |  |  |
+| **requiredNotNullable** | **string** |  |  |
+| **requiredNullable** | **string** |  |  |
+| **notRequiredNotNullable** | **string** |  | [optional]  |
+| **notRequiredNullable** | **string** |  | [optional]  |
 
 ### Return type
 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterBooleanSerializeAsyncTest()
         {
-            bool body = default;
+            Client.Option<bool> body = default;
             var response = await _instance.FakeOuterBooleanSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<bool>(model);
@@ -79,7 +79,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterCompositeSerializeAsyncTest()
         {
-            OuterComposite outerComposite = default;
+            Client.Option<OuterComposite> outerComposite = default;
             var response = await _instance.FakeOuterCompositeSerializeAsync(outerComposite);
             var model = response.AsModel();
             Assert.IsType<OuterComposite>(model);
@@ -91,7 +91,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterNumberSerializeAsyncTest()
         {
-            decimal body = default;
+            Client.Option<decimal> body = default;
             var response = await _instance.FakeOuterNumberSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<decimal>(model);
@@ -104,7 +104,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task FakeOuterStringSerializeAsyncTest()
         {
             Guid requiredStringUuid = default;
-            string body = default;
+            Client.Option<string> body = default;
             var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             var model = response.AsModel();
             Assert.IsType<string>(model);
@@ -164,16 +164,16 @@ namespace Org.OpenAPITools.Test.Api
             decimal number = default;
             double varDouble = default;
             string patternWithoutDelimiter = default;
-            DateTime date = default;
-            System.IO.Stream binary = default;
-            float varFloat = default;
-            int integer = default;
-            int int32 = default;
-            long int64 = default;
-            string varString = default;
-            string password = default;
-            string callback = default;
-            DateTime dateTime = default;
+            Client.Option<DateTime> date = default;
+            Client.Option<System.IO.Stream> binary = default;
+            Client.Option<float> varFloat = default;
+            Client.Option<int> integer = default;
+            Client.Option<int> int32 = default;
+            Client.Option<long> int64 = default;
+            Client.Option<string> varString = default;
+            Client.Option<string> password = default;
+            Client.Option<string> callback = default;
+            Client.Option<DateTime> dateTime = default;
             await _instance.TestEndpointParametersAsync(varByte, number, varDouble, patternWithoutDelimiter, date, binary, varFloat, integer, int32, int64, varString, password, callback, dateTime);
         }
 
@@ -183,14 +183,14 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task TestEnumParametersAsyncTest()
         {
-            List<string> enumHeaderStringArray = default;
-            List<string> enumQueryStringArray = default;
-            double enumQueryDouble = default;
-            int enumQueryInteger = default;
-            List<string> enumFormStringArray = default;
-            string enumHeaderString = default;
-            string enumQueryString = default;
-            string enumFormString = default;
+            Client.Option<List<string>> enumHeaderStringArray = default;
+            Client.Option<List<string>> enumQueryStringArray = default;
+            Client.Option<double> enumQueryDouble = default;
+            Client.Option<int> enumQueryInteger = default;
+            Client.Option<List<string>> enumFormStringArray = default;
+            Client.Option<string> enumHeaderString = default;
+            Client.Option<string> enumQueryString = default;
+            Client.Option<string> enumFormString = default;
             await _instance.TestEnumParametersAsync(enumHeaderStringArray, enumQueryStringArray, enumQueryDouble, enumQueryInteger, enumFormStringArray, enumHeaderString, enumQueryString, enumFormString);
         }
 
@@ -203,9 +203,9 @@ namespace Org.OpenAPITools.Test.Api
             bool requiredBooleanGroup = default;
             int requiredStringGroup = default;
             long requiredInt64Group = default;
-            bool booleanGroup = default;
-            int stringGroup = default;
-            long int64Group = default;
+            Client.Option<bool> booleanGroup = default;
+            Client.Option<int> stringGroup = default;
+            Client.Option<long> int64Group = default;
             await _instance.TestGroupParametersAsync(requiredBooleanGroup, requiredStringGroup, requiredInt64Group, booleanGroup, stringGroup, int64Group);
         }
 
@@ -241,7 +241,11 @@ namespace Org.OpenAPITools.Test.Api
             List<string> http = default;
             List<string> url = default;
             List<string> context = default;
-            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context);
+            string requiredNotNullable = default;
+            string requiredNullable = default;
+            Client.Option<string> notRequiredNotNullable = default;
+            Client.Option<string> notRequiredNullable = default;
+            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/PetApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task DeletePetAsyncTest()
         {
             long petId = default;
-            string apiKey = default;
+            Client.Option<string> apiKey = default;
             await _instance.DeletePetAsync(petId, apiKey);
         }
 
@@ -124,8 +124,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UpdatePetWithFormAsyncTest()
         {
             long petId = default;
-            string name = default;
-            string status = default;
+            Client.Option<string> name = default;
+            Client.Option<string> status = default;
             await _instance.UpdatePetWithFormAsync(petId, name, status);
         }
 
@@ -136,8 +136,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UploadFileAsyncTest()
         {
             long petId = default;
-            System.IO.Stream file = default;
-            string additionalMetadata = default;
+            Client.Option<System.IO.Stream> file = default;
+            Client.Option<string> additionalMetadata = default;
             var response = await _instance.UploadFileAsync(petId, file, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);
@@ -151,7 +151,7 @@ namespace Org.OpenAPITools.Test.Api
         {
             System.IO.Stream requiredFile = default;
             long petId = default;
-            string additionalMetadata = default;
+            Client.Option<string> additionalMetadata = default;
             var response = await _instance.UploadFileWithRequiredFileAsync(requiredFile, petId, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/AnotherFakeApi.cs

@@ -126,14 +126,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCall123TestSpecialTags(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -233,7 +227,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/DefaultApi.cs

@@ -277,14 +277,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetCountry(string country)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (country == null)
                 throw new ArgumentNullException(nameof(country));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -390,7 +384,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeClassnameTags123Api.cs

@@ -126,14 +126,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateTestClassname(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -244,7 +238,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/PetApi.cs

@@ -61,7 +61,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> DeletePetAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Deletes a pet
@@ -73,7 +73,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Finds Pets by status
@@ -179,7 +179,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Updates a pet in the store with form data
@@ -192,7 +192,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -206,7 +206,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -219,7 +219,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -233,7 +233,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -246,7 +246,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
     }
 }
 
@@ -324,14 +324,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateAddPet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -437,9 +431,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -448,7 +444,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -482,27 +478,17 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatDeletePet(ref long petId, ref string apiKey);
+        partial void FormatDeletePet(ref long petId, ref Option<string> apiKey);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="apiKey"></param>
         /// <returns></returns>
-        private void ValidateDeletePet(long petId, string apiKey)
+        private void ValidateDeletePet(Option<string> apiKey)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (apiKey == null)
+            if (apiKey.IsSet && apiKey.Value == null)
                 throw new ArgumentNullException(nameof(apiKey));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -511,7 +497,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string apiKey)
+        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey)
         {
             bool suppressDefaultLog = false;
             AfterDeletePet(ref suppressDefaultLog, apiResponseLocalVar, petId, apiKey);
@@ -526,7 +512,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string apiKey);
+        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -536,7 +522,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string apiKey)
+        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorDeletePet(exception, pathFormat, path, petId, apiKey);
@@ -550,7 +536,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, string apiKey);
+        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Deletes a pet 
@@ -559,7 +545,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -579,13 +565,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> DeletePetAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateDeletePet(petId, apiKey);
+                ValidateDeletePet(apiKey);
 
                 FormatDeletePet(ref petId, ref apiKey);
 
@@ -597,8 +583,8 @@ namespace Org.OpenAPITools.Api
                     uriBuilderLocalVar.Path = ClientUtils.CONTEXT_PATH + "/pet/{petId}";
                     uriBuilderLocalVar.Path = uriBuilderLocalVar.Path.Replace("%7BpetId%7D", Uri.EscapeDataString(petId.ToString()));
 
-                    if (apiKey != null)
-                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey));
+                    if (apiKey.IsSet)
+                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey.Value));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -646,14 +632,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByStatus(List<string> status)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (status == null)
                 throw new ArgumentNullException(nameof(status));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -761,9 +741,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -815,14 +797,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByTags(List<string> tags)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (tags == null)
                 throw new ArgumentNullException(nameof(tags));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -930,9 +906,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -977,23 +955,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetPetById(ref long petId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="petId"></param>
-        /// <returns></returns>
-        private void ValidateGetPetById(long petId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -1068,8 +1029,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetPetById(petId);
-
                 FormatGetPetById(ref petId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -1136,14 +1095,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateUpdatePet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1249,9 +1202,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -1260,7 +1215,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Put;
@@ -1294,31 +1249,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUpdatePetWithForm(ref long petId, ref string name, ref string status);
+        partial void FormatUpdatePetWithForm(ref long petId, ref Option<string> name, ref Option<string> status);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
-        /// <param name="name"></param>
         /// <param name="status"></param>
+        /// <param name="name"></param>
         /// <returns></returns>
-        private void ValidateUpdatePetWithForm(long petId, string name, string status)
+        private void ValidateUpdatePetWithForm(Option<string> status, Option<string> name)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (name == null)
-                throw new ArgumentNullException(nameof(name));
-
-            if (status == null)
+            if (status.IsSet && status.Value == null)
                 throw new ArgumentNullException(nameof(status));
 
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            if (name.IsSet && name.Value == null)
+                throw new ArgumentNullException(nameof(name));
         }
 
         /// <summary>
@@ -1328,7 +1273,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string name, string status)
+        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status)
         {
             bool suppressDefaultLog = false;
             AfterUpdatePetWithForm(ref suppressDefaultLog, apiResponseLocalVar, petId, name, status);
@@ -1344,7 +1289,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string name, string status);
+        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1355,7 +1300,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string name, string status)
+        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUpdatePetWithForm(exception, pathFormat, path, petId, name, status);
@@ -1370,7 +1315,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, string name, string status);
+        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Updates a pet in the store with form data 
@@ -1380,7 +1325,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1401,13 +1346,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUpdatePetWithForm(petId, name, status);
+                ValidateUpdatePetWithForm(status, name);
 
                 FormatUpdatePetWithForm(ref petId, ref name, ref status);
 
@@ -1425,11 +1370,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string, string>> formParameterLocalVars = new List<KeyValuePair<string, string>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("name", ClientUtils.ParameterToString(name)));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("name", ClientUtils.ParameterToString(name.Value)));
 
-                    if (status != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("status", ClientUtils.ParameterToString(status)));
+                    if (status.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("status", ClientUtils.ParameterToString(status.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1447,7 +1392,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -1477,31 +1422,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFile(ref long petId, ref System.IO.Stream file, ref string additionalMetadata);
+        partial void FormatUploadFile(ref long petId, ref Option<System.IO.Stream> file, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
         /// <returns></returns>
-        private void ValidateUploadFile(long petId, System.IO.Stream file, string additionalMetadata)
+        private void ValidateUploadFile(Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (file == null)
+            if (file.IsSet && file.Value == null)
                 throw new ArgumentNullException(nameof(file));
 
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1511,7 +1446,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream file, string additionalMetadata)
+        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFile(ref suppressDefaultLog, apiResponseLocalVar, petId, file, additionalMetadata);
@@ -1527,7 +1462,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream file, string additionalMetadata);
+        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1538,7 +1473,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, System.IO.Stream file, string additionalMetadata)
+        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFile(exception, pathFormat, path, petId, file, additionalMetadata);
@@ -1553,7 +1488,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, System.IO.Stream file, string additionalMetadata);
+        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image 
@@ -1563,7 +1498,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1584,13 +1519,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFile(petId, file, additionalMetadata);
+                ValidateUploadFile(file, additionalMetadata);
 
                 FormatUploadFile(ref petId, ref file, ref additionalMetadata);
 
@@ -1608,11 +1543,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string, string>> formParameterLocalVars = new List<KeyValuePair<string, string>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file != null)
-                        multipartContentLocalVar.Add(new StreamContent(file));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file.IsSet)
+                        multipartContentLocalVar.Add(new StreamContent(file.Value));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1630,7 +1565,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {
@@ -1669,31 +1604,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref string additionalMetadata);
+        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
         /// <param name="requiredFile"></param>
-        /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
         /// <returns></returns>
-        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, Option<string> additionalMetadata)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (requiredFile == null)
                 throw new ArgumentNullException(nameof(requiredFile));
 
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1703,7 +1628,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFileWithRequiredFile(ref suppressDefaultLog, apiResponseLocalVar, requiredFile, petId, additionalMetadata);
@@ -1719,7 +1644,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string additionalMetadata);
+        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1730,7 +1655,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFileWithRequiredFile(exception, pathFormat, path, requiredFile, petId, additionalMetadata);
@@ -1745,7 +1670,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string additionalMetadata);
+        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image (required) 
@@ -1755,7 +1680,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1776,13 +1701,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFileWithRequiredFile(requiredFile, petId, additionalMetadata);
+                ValidateUploadFileWithRequiredFile(requiredFile, additionalMetadata);
 
                 FormatUploadFileWithRequiredFile(ref requiredFile, ref petId, ref additionalMetadata);
 
@@ -1802,8 +1727,8 @@ namespace Org.OpenAPITools.Api
 
                     multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    multipartContentLocalVar.Add(new StreamContent(requiredFile));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1821,7 +1746,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/StoreApi.cs

@@ -193,14 +193,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteOrder(string orderId)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (orderId == null)
                 throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -437,23 +431,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetOrderById(ref long orderId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="orderId"></param>
-        /// <returns></returns>
-        private void ValidateGetOrderById(long orderId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (orderId == null)
-                throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -528,8 +505,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetOrderById(orderId);
-
                 FormatGetOrderById(ref orderId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -584,14 +559,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidatePlaceOrder(Order order)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (order == null)
                 throw new ArgumentNullException(nameof(order));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -691,7 +660,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/UserApi.cs

@@ -289,14 +289,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUser(User user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -396,7 +390,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -431,14 +425,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithArrayInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -538,7 +526,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -573,14 +561,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithListInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -680,7 +662,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Post;
@@ -715,14 +697,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteUser(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -845,14 +821,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetUserByName(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -986,17 +956,11 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateLoginUser(string username, string password)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
 
             if (password == null)
                 throw new ArgumentNullException(nameof(password));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1237,22 +1201,16 @@ namespace Org.OpenAPITools.Api
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="user"></param>
         /// <param name="username"></param>
+        /// <param name="user"></param>
         /// <returns></returns>
-        private void ValidateUpdateUser(User user, string username)
+        private void ValidateUpdateUser(string username, User user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
 
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            if (user == null)
+                throw new ArgumentNullException(nameof(user));
         }
 
         /// <summary>
@@ -1335,7 +1293,7 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateUpdateUser(user, username);
+                ValidateUpdateUser(username, user);
 
                 FormatUpdateUser(user, ref username);
 
@@ -1359,7 +1317,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = HttpMethod.Put;

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,39 @@
+// <auto-generated>
+/*
+ * OpenAPI Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/AdditionalPropertiesClass.cs

@@ -275,13 +275,20 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, AdditionalPropertiesClass additionalPropertiesClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("empty_map");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);            writer.WritePropertyName("map_of_map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_string");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);            writer.WritePropertyName("anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_string");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);
+            writer.WritePropertyName("anytype_1");
             JsonSerializer.Serialize(writer, additionalPropertiesClass.Anytype1, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/ArrayTest.cs

@@ -192,8 +192,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ArrayTest arrayTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_array_of_integer");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);            writer.WritePropertyName("array_array_of_model");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);            writer.WritePropertyName("array_of_string");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);
+            writer.WritePropertyName("array_array_of_model");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);
+            writer.WritePropertyName("array_of_string");
             JsonSerializer.Serialize(writer, arrayTest.ArrayOfString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/Drawing.cs

@@ -197,9 +197,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Drawing drawing, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("mainShape");
-            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);            writer.WritePropertyName("shapes");
-            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);            writer.WritePropertyName("nullableShape");
-            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);            writer.WritePropertyName("shapeOrNull");
+            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapes");
+            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);
+            writer.WritePropertyName("nullableShape");
+            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapeOrNull");
             JsonSerializer.Serialize(writer, drawing.ShapeOrNull, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/EnumArrays.cs

@@ -310,6 +310,7 @@ namespace Org.OpenAPITools.Model
         {
             writer.WritePropertyName("array_enum");
             JsonSerializer.Serialize(writer, enumArrays.ArrayEnum, jsonSerializerOptions);
+
             var justSymbolRawValue = EnumArrays.JustSymbolEnumToJsonValue(enumArrays.JustSymbol);
             if (justSymbolRawValue != null)
                 writer.WriteString("just_symbol", justSymbolRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/FileSchemaTestClass.cs

@@ -175,7 +175,8 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FileSchemaTestClass fileSchemaTestClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("file");
-            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);            writer.WritePropertyName("files");
+            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);
+            writer.WritePropertyName("files");
             JsonSerializer.Serialize(writer, fileSchemaTestClass.Files, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/FormatTest.cs

@@ -587,11 +587,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FormatTest formatTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("binary");
-            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);            writer.WritePropertyName("byte");
-            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
+            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);
+            writer.WritePropertyName("byte");
+            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);
+            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
             writer.WriteString("dateTime", formatTest.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("decimal");
-            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);            writer.WriteNumber("double", formatTest.VarDouble);
+            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);
+            writer.WriteNumber("double", formatTest.VarDouble);
             writer.WriteNumber("float", formatTest.VarFloat);
             writer.WriteNumber("int32", formatTest.Int32);
             writer.WriteNumber("int64", formatTest.Int64);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MapTest.cs

@@ -275,9 +275,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, MapTest mapTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("direct_map");
-            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);            writer.WritePropertyName("indirect_map");
-            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);            writer.WritePropertyName("map_map_of_string");
-            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);            writer.WritePropertyName("map_of_enum_string");
+            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("indirect_map");
+            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_map_of_string");
+            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_enum_string");
             JsonSerializer.Serialize(writer, mapTest.MapOfEnumString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs

@@ -222,7 +222,8 @@ namespace Org.OpenAPITools.Model
         {
             writer.WriteString("dateTime", mixedPropertiesAndAdditionalPropertiesClass.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("map");
-            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
+            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
             writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/NullableClass.cs

@@ -318,10 +318,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, NullableClass nullableClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("object_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("array_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("array_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("object_items_nullable");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("array_and_items_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("array_nullable_prop");
             JsonSerializer.Serialize(writer, nullableClass.ArrayNullableProp, jsonSerializerOptions);
+
             if (nullableClass.BooleanProp != null)
                 writer.WriteBoolean("boolean_prop", nullableClass.BooleanProp.Value);
             else
@@ -348,8 +352,10 @@ namespace Org.OpenAPITools.Model
                 writer.WriteNull("number_prop");
 
             writer.WritePropertyName("object_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("object_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);            writer.WriteString("string_prop", nullableClass.StringProp);
+            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("object_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);
+            writer.WriteString("string_prop", nullableClass.StringProp);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs

@@ -211,8 +211,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ObjectWithDeprecatedFields objectWithDeprecatedFields, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("bars");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);            writer.WritePropertyName("deprecatedRef");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);
+            writer.WritePropertyName("deprecatedRef");
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);
+            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
             writer.WriteString("uuid", objectWithDeprecatedFields.Uuid);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/Pet.cs

@@ -327,10 +327,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Pet pet, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("category");
-            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);            writer.WriteNumber("id", pet.Id);
+            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);
+            writer.WriteNumber("id", pet.Id);
             writer.WriteString("name", pet.Name);
             writer.WritePropertyName("photoUrls");
             JsonSerializer.Serialize(writer, pet.PhotoUrls, jsonSerializerOptions);
+
             var statusRawValue = Pet.StatusEnumToJsonValue(pet.Status);
             if (statusRawValue != null)
                 writer.WriteString("status", statusRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/User.cs

@@ -339,13 +339,16 @@ namespace Org.OpenAPITools.Model
             writer.WriteNumber("id", user.Id);
             writer.WriteString("lastName", user.LastName);
             writer.WritePropertyName("objectWithNoDeclaredProps");
-            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);            writer.WriteString("password", user.Password);
+            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);
+            writer.WriteString("password", user.Password);
             writer.WriteString("phone", user.Phone);
             writer.WriteNumber("userStatus", user.UserStatus);
             writer.WriteString("username", user.Username);
             writer.WritePropertyName("anyTypeProp");
-            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);            writer.WritePropertyName("anyTypePropNullable");
-            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);
+            writer.WritePropertyName("anyTypePropNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);
+            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
             JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredPropsNullable, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-allOf/.openapi-generator/FILES

@@ -24,6 +24,7 @@ src/Org.OpenAPITools/Client/DateTimeJsonConverter.cs
 src/Org.OpenAPITools/Client/DateTimeNullableJsonConverter.cs
 src/Org.OpenAPITools/Client/HostConfiguration.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-allOf/src/Org.OpenAPITools/Api/DefaultApi.cs

@@ -93,14 +93,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateList(string personId)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (personId == null)
                 throw new ArgumentNullException(nameof(personId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-allOf/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,41 @@
+// <auto-generated>
+/*
+ * Example
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+#nullable enable
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-allOf/src/Org.OpenAPITools/Model/Adult.cs

@@ -168,7 +168,8 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Adult adult, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("children");
-            JsonSerializer.Serialize(writer, adult.Children, jsonSerializerOptions);            writer.WriteString("firstName", adult.FirstName);
+            JsonSerializer.Serialize(writer, adult.Children, jsonSerializerOptions);
+            writer.WriteString("firstName", adult.FirstName);
             writer.WriteString("lastName", adult.LastName);
             writer.WriteString("$_type", adult.Type);
         }

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-anyOf/.openapi-generator/FILES

@@ -24,6 +24,7 @@ src/Org.OpenAPITools/Client/DateTimeJsonConverter.cs
 src/Org.OpenAPITools/Client/DateTimeNullableJsonConverter.cs
 src/Org.OpenAPITools/Client/HostConfiguration.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-anyOf/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,41 @@
+// <auto-generated>
+/*
+ * fruity
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+#nullable enable
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-oneOf/.openapi-generator/FILES

@@ -24,6 +24,7 @@ src/Org.OpenAPITools/Client/DateTimeJsonConverter.cs
 src/Org.OpenAPITools/Client/DateTimeNullableJsonConverter.cs
 src/Org.OpenAPITools/Client/HostConfiguration.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-netcore-latest-oneOf/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,41 @@
+// <auto-generated>
+/*
+ * fruity
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+#nullable enable
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/.openapi-generator/FILES

@@ -123,6 +123,7 @@ src/Org.OpenAPITools/Client/HttpSigningConfiguration.cs
 src/Org.OpenAPITools/Client/HttpSigningToken.cs
 src/Org.OpenAPITools/Client/JsonSerializerOptionsProvider.cs
 src/Org.OpenAPITools/Client/OAuthToken.cs
+src/Org.OpenAPITools/Client/Option.cs
 src/Org.OpenAPITools/Client/RateLimitProvider`1.cs
 src/Org.OpenAPITools/Client/TokenBase.cs
 src/Org.OpenAPITools/Client/TokenContainer`1.cs

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/api/openapi.yaml

@@ -1036,6 +1036,38 @@ paths:
             type: string
           type: array
         style: form
+      - explode: true
+        in: query
+        name: requiredNotNullable
+        required: true
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: requiredNullable
+        required: true
+        schema:
+          nullable: true
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNotNullable
+        required: false
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNullable
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: form
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/docs/apis/FakeApi.md

@@ -1301,7 +1301,7 @@ No authorization required
 
 <a id="testqueryparametercollectionformat"></a>
 # **TestQueryParameterCollectionFormat**
-> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context)
+> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = null, string notRequiredNullable = null)
 
 
 
@@ -1329,10 +1329,14 @@ namespace Example
             var http = new List<string>(); // List<string> | 
             var url = new List<string>(); // List<string> | 
             var context = new List<string>(); // List<string> | 
+            var requiredNotNullable = "requiredNotNullable_example";  // string | 
+            var requiredNullable = "requiredNullable_example";  // string | 
+            var notRequiredNotNullable = "notRequiredNotNullable_example";  // string |  (optional) 
+            var notRequiredNullable = "notRequiredNullable_example";  // string |  (optional) 
 
             try
             {
-                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
+                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
             }
             catch (ApiException  e)
             {
@@ -1351,7 +1355,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
 }
 catch (ApiException e)
 {
@@ -1370,6 +1374,10 @@ catch (ApiException e)
 | **http** | [**List&lt;string&gt;**](string.md) |  |  |
 | **url** | [**List&lt;string&gt;**](string.md) |  |  |
 | **context** | [**List&lt;string&gt;**](string.md) |  |  |
+| **requiredNotNullable** | **string** |  |  |
+| **requiredNullable** | **string** |  |  |
+| **notRequiredNotNullable** | **string** |  | [optional]  |
+| **notRequiredNullable** | **string** |  | [optional]  |
 
 ### Return type
 

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterBooleanSerializeAsyncTest()
         {
-            bool body = default;
+            Client.Option<bool> body = default;
             var response = await _instance.FakeOuterBooleanSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<bool>(model);
@@ -79,7 +79,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterCompositeSerializeAsyncTest()
         {
-            OuterComposite outerComposite = default;
+            Client.Option<OuterComposite> outerComposite = default;
             var response = await _instance.FakeOuterCompositeSerializeAsync(outerComposite);
             var model = response.AsModel();
             Assert.IsType<OuterComposite>(model);
@@ -91,7 +91,7 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterNumberSerializeAsyncTest()
         {
-            decimal body = default;
+            Client.Option<decimal> body = default;
             var response = await _instance.FakeOuterNumberSerializeAsync(body);
             var model = response.AsModel();
             Assert.IsType<decimal>(model);
@@ -104,7 +104,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task FakeOuterStringSerializeAsyncTest()
         {
             Guid requiredStringUuid = default;
-            string body = default;
+            Client.Option<string> body = default;
             var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             var model = response.AsModel();
             Assert.IsType<string>(model);
@@ -164,16 +164,16 @@ namespace Org.OpenAPITools.Test.Api
             decimal number = default;
             double varDouble = default;
             string patternWithoutDelimiter = default;
-            DateTime date = default;
-            System.IO.Stream binary = default;
-            float varFloat = default;
-            int integer = default;
-            int int32 = default;
-            long int64 = default;
-            string varString = default;
-            string password = default;
-            string callback = default;
-            DateTime dateTime = default;
+            Client.Option<DateTime> date = default;
+            Client.Option<System.IO.Stream> binary = default;
+            Client.Option<float> varFloat = default;
+            Client.Option<int> integer = default;
+            Client.Option<int> int32 = default;
+            Client.Option<long> int64 = default;
+            Client.Option<string> varString = default;
+            Client.Option<string> password = default;
+            Client.Option<string> callback = default;
+            Client.Option<DateTime> dateTime = default;
             await _instance.TestEndpointParametersAsync(varByte, number, varDouble, patternWithoutDelimiter, date, binary, varFloat, integer, int32, int64, varString, password, callback, dateTime);
         }
 
@@ -183,14 +183,14 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task TestEnumParametersAsyncTest()
         {
-            List<string> enumHeaderStringArray = default;
-            List<string> enumQueryStringArray = default;
-            double enumQueryDouble = default;
-            int enumQueryInteger = default;
-            List<string> enumFormStringArray = default;
-            string enumHeaderString = default;
-            string enumQueryString = default;
-            string enumFormString = default;
+            Client.Option<List<string>> enumHeaderStringArray = default;
+            Client.Option<List<string>> enumQueryStringArray = default;
+            Client.Option<double> enumQueryDouble = default;
+            Client.Option<int> enumQueryInteger = default;
+            Client.Option<List<string>> enumFormStringArray = default;
+            Client.Option<string> enumHeaderString = default;
+            Client.Option<string> enumQueryString = default;
+            Client.Option<string> enumFormString = default;
             await _instance.TestEnumParametersAsync(enumHeaderStringArray, enumQueryStringArray, enumQueryDouble, enumQueryInteger, enumFormStringArray, enumHeaderString, enumQueryString, enumFormString);
         }
 
@@ -203,9 +203,9 @@ namespace Org.OpenAPITools.Test.Api
             bool requiredBooleanGroup = default;
             int requiredStringGroup = default;
             long requiredInt64Group = default;
-            bool booleanGroup = default;
-            int stringGroup = default;
-            long int64Group = default;
+            Client.Option<bool> booleanGroup = default;
+            Client.Option<int> stringGroup = default;
+            Client.Option<long> int64Group = default;
             await _instance.TestGroupParametersAsync(requiredBooleanGroup, requiredStringGroup, requiredInt64Group, booleanGroup, stringGroup, int64Group);
         }
 
@@ -241,7 +241,11 @@ namespace Org.OpenAPITools.Test.Api
             List<string> http = default;
             List<string> url = default;
             List<string> context = default;
-            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context);
+            string requiredNotNullable = default;
+            string requiredNullable = default;
+            Client.Option<string> notRequiredNotNullable = default;
+            Client.Option<string> notRequiredNullable = default;
+            await _instance.TestQueryParameterCollectionFormatAsync(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/PetApiTests.cs

@@ -67,7 +67,7 @@ namespace Org.OpenAPITools.Test.Api
         public async Task DeletePetAsyncTest()
         {
             long petId = default;
-            string apiKey = default;
+            Client.Option<string> apiKey = default;
             await _instance.DeletePetAsync(petId, apiKey);
         }
 
@@ -124,8 +124,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UpdatePetWithFormAsyncTest()
         {
             long petId = default;
-            string name = default;
-            string status = default;
+            Client.Option<string> name = default;
+            Client.Option<string> status = default;
             await _instance.UpdatePetWithFormAsync(petId, name, status);
         }
 
@@ -136,8 +136,8 @@ namespace Org.OpenAPITools.Test.Api
         public async Task UploadFileAsyncTest()
         {
             long petId = default;
-            System.IO.Stream file = default;
-            string additionalMetadata = default;
+            Client.Option<System.IO.Stream> file = default;
+            Client.Option<string> additionalMetadata = default;
             var response = await _instance.UploadFileAsync(petId, file, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);
@@ -151,7 +151,7 @@ namespace Org.OpenAPITools.Test.Api
         {
             System.IO.Stream requiredFile = default;
             long petId = default;
-            string additionalMetadata = default;
+            Client.Option<string> additionalMetadata = default;
             var response = await _instance.UploadFileWithRequiredFileAsync(requiredFile, petId, additionalMetadata);
             var model = response.AsModel();
             Assert.IsType<ApiResponse>(model);

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/AnotherFakeApi.cs

@@ -126,14 +126,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCall123TestSpecialTags(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -233,7 +227,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/DefaultApi.cs

@@ -276,14 +276,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetCountry(string country)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (country == null)
                 throw new ArgumentNullException(nameof(country));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -389,7 +383,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeClassnameTags123Api.cs

@@ -126,14 +126,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateTestClassname(ModelClient modelClient)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (modelClient == null)
                 throw new ArgumentNullException(nameof(modelClient));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -244,7 +238,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/PetApi.cs

@@ -61,7 +61,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> DeletePetAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Deletes a pet
@@ -73,7 +73,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Finds Pets by status
@@ -179,7 +179,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Updates a pet in the store with form data
@@ -192,7 +192,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;object&gt;&gt;</returns>
-        Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -206,7 +206,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image
@@ -219,7 +219,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -233,7 +233,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
 
         /// <summary>
         /// uploads an image (required)
@@ -246,7 +246,7 @@ namespace Org.OpenAPITools.IApi
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&gt;ApiResponse&gt;&gt;</returns>
-        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default);
+        Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default);
     }
 }
 
@@ -324,14 +324,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateAddPet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -437,9 +431,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -448,7 +444,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");
@@ -482,27 +478,17 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatDeletePet(ref long petId, ref string apiKey);
+        partial void FormatDeletePet(ref long petId, ref Option<string> apiKey);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="apiKey"></param>
         /// <returns></returns>
-        private void ValidateDeletePet(long petId, string apiKey)
+        private void ValidateDeletePet(Option<string> apiKey)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (apiKey == null)
+            if (apiKey.IsSet && apiKey.Value == null)
                 throw new ArgumentNullException(nameof(apiKey));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -511,7 +497,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string apiKey)
+        private void AfterDeletePetDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey)
         {
             bool suppressDefaultLog = false;
             AfterDeletePet(ref suppressDefaultLog, apiResponseLocalVar, petId, apiKey);
@@ -526,7 +512,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiResponseLocalVar"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string apiKey);
+        partial void AfterDeletePet(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -536,7 +522,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string apiKey)
+        private void OnErrorDeletePetDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorDeletePet(exception, pathFormat, path, petId, apiKey);
@@ -550,7 +536,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="path"></param>
         /// <param name="petId"></param>
         /// <param name="apiKey"></param>
-        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, string apiKey);
+        partial void OnErrorDeletePet(Exception exception, string pathFormat, string path, long petId, Option<string> apiKey);
 
         /// <summary>
         /// Deletes a pet 
@@ -559,7 +545,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> DeletePetOrDefaultAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -579,13 +565,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="apiKey"> (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> DeletePetAsync(long petId, string apiKey = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> DeletePetAsync(long petId, Option<string> apiKey = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateDeletePet(petId, apiKey);
+                ValidateDeletePet(apiKey);
 
                 FormatDeletePet(ref petId, ref apiKey);
 
@@ -597,8 +583,8 @@ namespace Org.OpenAPITools.Api
                     uriBuilderLocalVar.Path = ClientUtils.CONTEXT_PATH + "/pet/{petId}";
                     uriBuilderLocalVar.Path = uriBuilderLocalVar.Path.Replace("%7BpetId%7D", Uri.EscapeDataString(petId.ToString()));
 
-                    if (apiKey != null)
-                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey));
+                    if (apiKey.IsSet)
+                        httpRequestMessageLocalVar.Headers.Add("api_key", ClientUtils.ParameterToString(apiKey.Value));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -645,14 +631,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByStatus(List<string> status)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (status == null)
                 throw new ArgumentNullException(nameof(status));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -760,9 +740,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -813,14 +795,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateFindPetsByTags(List<string> tags)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (tags == null)
                 throw new ArgumentNullException(nameof(tags));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -928,9 +904,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] acceptLocalVars = new string[] {
                         "application/xml",
@@ -974,23 +952,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetPetById(ref long petId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="petId"></param>
-        /// <returns></returns>
-        private void ValidateGetPetById(long petId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -1065,8 +1026,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetPetById(petId);
-
                 FormatGetPetById(ref petId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -1132,14 +1091,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateUpdatePet(Pet pet)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (pet == null)
                 throw new ArgumentNullException(nameof(pet));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1245,9 +1198,11 @@ namespace Org.OpenAPITools.Api
 
                     tokenBaseLocalVars.Add(httpSignatureTokenLocalVar);
 
-                    string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
+                    if (httpRequestMessageLocalVar.Content != null) {
+                        string requestBodyLocalVar = await httpRequestMessageLocalVar.Content.ReadAsStringAsync().ConfigureAwait(false);
 
-                    httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                        httpSignatureTokenLocalVar.UseInHeader(httpRequestMessageLocalVar, requestBodyLocalVar, cancellationToken);
+                    }
 
                     string[] contentTypes = new string[] {
                         "application/json",
@@ -1256,7 +1211,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("PUT");
@@ -1290,31 +1245,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUpdatePetWithForm(ref long petId, ref string name, ref string status);
+        partial void FormatUpdatePetWithForm(ref long petId, ref Option<string> name, ref Option<string> status);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
-        /// <param name="name"></param>
         /// <param name="status"></param>
+        /// <param name="name"></param>
         /// <returns></returns>
-        private void ValidateUpdatePetWithForm(long petId, string name, string status)
+        private void ValidateUpdatePetWithForm(Option<string> status, Option<string> name)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (name == null)
-                throw new ArgumentNullException(nameof(name));
-
-            if (status == null)
+            if (status.IsSet && status.Value == null)
                 throw new ArgumentNullException(nameof(status));
 
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            if (name.IsSet && name.Value == null)
+                throw new ArgumentNullException(nameof(name));
         }
 
         /// <summary>
@@ -1324,7 +1269,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, string name, string status)
+        private void AfterUpdatePetWithFormDefaultImplementation(ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status)
         {
             bool suppressDefaultLog = false;
             AfterUpdatePetWithForm(ref suppressDefaultLog, apiResponseLocalVar, petId, name, status);
@@ -1340,7 +1285,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, string name, string status);
+        partial void AfterUpdatePetWithForm(ref bool suppressDefaultLog, ApiResponse<object> apiResponseLocalVar, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1351,7 +1296,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, string name, string status)
+        private void OnErrorUpdatePetWithFormDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUpdatePetWithForm(exception, pathFormat, path, petId, name, status);
@@ -1366,7 +1311,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="name"></param>
         /// <param name="status"></param>
-        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, string name, string status);
+        partial void OnErrorUpdatePetWithForm(Exception exception, string pathFormat, string path, long petId, Option<string> name, Option<string> status);
 
         /// <summary>
         /// Updates a pet in the store with form data 
@@ -1376,7 +1321,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> UpdatePetWithFormOrDefaultAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1397,13 +1342,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="status">Updated status of the pet (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="object"/></returns>
-        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, string name = null, string status = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<object>> UpdatePetWithFormAsync(long petId, Option<string> name = default, Option<string> status = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUpdatePetWithForm(petId, name, status);
+                ValidateUpdatePetWithForm(status, name);
 
                 FormatUpdatePetWithForm(ref petId, ref name, ref status);
 
@@ -1421,11 +1366,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string, string>> formParameterLocalVars = new List<KeyValuePair<string, string>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("name", ClientUtils.ParameterToString(name)));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (name.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("name", ClientUtils.ParameterToString(name.Value)));
 
-                    if (status != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("status", ClientUtils.ParameterToString(status)));
+                    if (status.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("status", ClientUtils.ParameterToString(status.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1443,7 +1388,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");
@@ -1473,31 +1418,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFile(ref long petId, ref System.IO.Stream file, ref string additionalMetadata);
+        partial void FormatUploadFile(ref long petId, ref Option<System.IO.Stream> file, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
         /// <returns></returns>
-        private void ValidateUploadFile(long petId, System.IO.Stream file, string additionalMetadata)
+        private void ValidateUploadFile(Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (file == null)
+            if (file.IsSet && file.Value == null)
                 throw new ArgumentNullException(nameof(file));
 
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1507,7 +1442,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream file, string additionalMetadata)
+        private void AfterUploadFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFile(ref suppressDefaultLog, apiResponseLocalVar, petId, file, additionalMetadata);
@@ -1523,7 +1458,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, System.IO.Stream file, string additionalMetadata);
+        partial void AfterUploadFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1534,7 +1469,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, System.IO.Stream file, string additionalMetadata)
+        private void OnErrorUploadFileDefaultImplementation(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFile(exception, pathFormat, path, petId, file, additionalMetadata);
@@ -1549,7 +1484,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="petId"></param>
         /// <param name="file"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, System.IO.Stream file, string additionalMetadata);
+        partial void OnErrorUploadFile(Exception exception, string pathFormat, string path, long petId, Option<System.IO.Stream> file, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image 
@@ -1559,7 +1494,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileOrDefaultAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1580,13 +1515,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, System.IO.Stream file = null, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileAsync(long petId, Option<System.IO.Stream> file = default, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFile(petId, file, additionalMetadata);
+                ValidateUploadFile(file, additionalMetadata);
 
                 FormatUploadFile(ref petId, ref file, ref additionalMetadata);
 
@@ -1604,11 +1539,11 @@ namespace Org.OpenAPITools.Api
 
                     List<KeyValuePair<string, string>> formParameterLocalVars = new List<KeyValuePair<string, string>>();
 
-                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file != null)
-                        multipartContentLocalVar.Add(new StreamContent(file));
+                    multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    if (file.IsSet)
+                        multipartContentLocalVar.Add(new StreamContent(file.Value));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1626,7 +1561,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {
@@ -1664,31 +1599,21 @@ namespace Org.OpenAPITools.Api
             }
         }
 
-        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref string additionalMetadata);
+        partial void FormatUploadFileWithRequiredFile(ref System.IO.Stream requiredFile, ref long petId, ref Option<string> additionalMetadata);
 
         /// <summary>
         /// Validates the request parameters
         /// </summary>
         /// <param name="requiredFile"></param>
-        /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
         /// <returns></returns>
-        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void ValidateUploadFileWithRequiredFile(System.IO.Stream requiredFile, Option<string> additionalMetadata)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (requiredFile == null)
                 throw new ArgumentNullException(nameof(requiredFile));
 
-            if (petId == null)
-                throw new ArgumentNullException(nameof(petId));
-
-            if (additionalMetadata == null)
+            if (additionalMetadata.IsSet && additionalMetadata.Value == null)
                 throw new ArgumentNullException(nameof(additionalMetadata));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1698,7 +1623,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void AfterUploadFileWithRequiredFileDefaultImplementation(ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             bool suppressDefaultLog = false;
             AfterUploadFileWithRequiredFile(ref suppressDefaultLog, apiResponseLocalVar, requiredFile, petId, additionalMetadata);
@@ -1714,7 +1639,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, string additionalMetadata);
+        partial void AfterUploadFileWithRequiredFile(ref bool suppressDefaultLog, ApiResponse<ApiResponse> apiResponseLocalVar, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// Logs exceptions that occur while retrieving the server response
@@ -1725,7 +1650,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string additionalMetadata)
+        private void OnErrorUploadFileWithRequiredFileDefaultImplementation(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
             OnErrorUploadFileWithRequiredFile(exception, pathFormat, path, requiredFile, petId, additionalMetadata);
@@ -1740,7 +1665,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="requiredFile"></param>
         /// <param name="petId"></param>
         /// <param name="additionalMetadata"></param>
-        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, string additionalMetadata);
+        partial void OnErrorUploadFileWithRequiredFile(Exception exception, string pathFormat, string path, System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata);
 
         /// <summary>
         /// uploads an image (required) 
@@ -1750,7 +1675,7 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileOrDefaultAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             try
             {
@@ -1771,13 +1696,13 @@ namespace Org.OpenAPITools.Api
         /// <param name="additionalMetadata">Additional data to pass to server (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="ApiResponse"/></returns>
-        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, string additionalMetadata = null, System.Threading.CancellationToken cancellationToken = default)
+        public async Task<ApiResponse<ApiResponse>> UploadFileWithRequiredFileAsync(System.IO.Stream requiredFile, long petId, Option<string> additionalMetadata = default, System.Threading.CancellationToken cancellationToken = default)
         {
             UriBuilder uriBuilderLocalVar = new UriBuilder();
 
             try
             {
-                ValidateUploadFileWithRequiredFile(requiredFile, petId, additionalMetadata);
+                ValidateUploadFileWithRequiredFile(requiredFile, additionalMetadata);
 
                 FormatUploadFileWithRequiredFile(ref requiredFile, ref petId, ref additionalMetadata);
 
@@ -1797,8 +1722,8 @@ namespace Org.OpenAPITools.Api
 
                     multipartContentLocalVar.Add(new FormUrlEncodedContent(formParameterLocalVars));                    multipartContentLocalVar.Add(new StreamContent(requiredFile));
 
-                    if (additionalMetadata != null)
-                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata)));
+                    if (additionalMetadata.IsSet)
+                        formParameterLocalVars.Add(new KeyValuePair<string, string>("additionalMetadata", ClientUtils.ParameterToString(additionalMetadata.Value)));
 
                     List<TokenBase> tokenBaseLocalVars = new List<TokenBase>();
 
@@ -1816,7 +1741,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/StoreApi.cs

@@ -193,14 +193,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteOrder(string orderId)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (orderId == null)
                 throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -435,23 +429,6 @@ namespace Org.OpenAPITools.Api
 
         partial void FormatGetOrderById(ref long orderId);
 
-        /// <summary>
-        /// Validates the request parameters
-        /// </summary>
-        /// <param name="orderId"></param>
-        /// <returns></returns>
-        private void ValidateGetOrderById(long orderId)
-        {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (orderId == null)
-                throw new ArgumentNullException(nameof(orderId));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-        }
-
         /// <summary>
         /// Processes the server response
         /// </summary>
@@ -526,8 +503,6 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateGetOrderById(orderId);
-
                 FormatGetOrderById(ref orderId);
 
                 using (HttpRequestMessage httpRequestMessageLocalVar = new HttpRequestMessage())
@@ -581,14 +556,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidatePlaceOrder(Order order)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (order == null)
                 throw new ArgumentNullException(nameof(order));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -688,7 +657,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     string[] acceptLocalVars = new string[] {

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/UserApi.cs

@@ -289,14 +289,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUser(User user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -396,7 +390,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");
@@ -431,14 +425,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithArrayInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -538,7 +526,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");
@@ -573,14 +561,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateCreateUsersWithListInput(List<User> user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -680,7 +662,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("POST");
@@ -715,14 +697,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateDeleteUser(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -844,14 +820,8 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateGetUserByName(string username)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -984,17 +954,11 @@ namespace Org.OpenAPITools.Api
         /// <returns></returns>
         private void ValidateLoginUser(string username, string password)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
 
             if (password == null)
                 throw new ArgumentNullException(nameof(password));
-
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
         }
 
         /// <summary>
@@ -1233,22 +1197,16 @@ namespace Org.OpenAPITools.Api
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="user"></param>
         /// <param name="username"></param>
+        /// <param name="user"></param>
         /// <returns></returns>
-        private void ValidateUpdateUser(User user, string username)
+        private void ValidateUpdateUser(string username, User user)
         {
-            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
-
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
 
-            #pragma warning restore CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
-            #pragma warning restore CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            if (user == null)
+                throw new ArgumentNullException(nameof(user));
         }
 
         /// <summary>
@@ -1331,7 +1289,7 @@ namespace Org.OpenAPITools.Api
 
             try
             {
-                ValidateUpdateUser(user, username);
+                ValidateUpdateUser(username, user);
 
                 FormatUpdateUser(user, ref username);
 
@@ -1355,7 +1313,7 @@ namespace Org.OpenAPITools.Api
 
                     string contentTypeLocalVar = ClientUtils.SelectHeaderContentType(contentTypes);
 
-                    if (contentTypeLocalVar != null)
+                    if (contentTypeLocalVar != null && httpRequestMessageLocalVar.Content != null)
                         httpRequestMessageLocalVar.Content.Headers.ContentType = new MediaTypeHeaderValue(contentTypeLocalVar);
 
                     httpRequestMessageLocalVar.Method = new HttpMethod("PUT");

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Client/Option.cs

@@ -0,0 +1,39 @@
+// <auto-generated>
+/*
+ * OpenAPI Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+
+namespace Org.OpenAPITools.Client
+{
+    /// <summary>
+    /// A wrapper for operation parameters which are not required
+    /// </summary>
+    public struct Option<TType>
+    {
+        /// <summary>
+        /// The value to send to the server
+        /// </summary>
+        public TType Value { get; }
+
+        /// <summary>
+        /// When true the value will be sent to the server
+        /// </summary>
+        internal bool IsSet { get; }
+
+        /// <summary>
+        /// A wrapper for operation parameters which are not required
+        /// </summary>
+        /// <param name="value"></param>
+        public Option(TType value)
+        {
+            IsSet = true;
+            Value = value;
+        }
+    }
+}

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/AdditionalPropertiesClass.cs

@@ -275,13 +275,20 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, AdditionalPropertiesClass additionalPropertiesClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("empty_map");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);            writer.WritePropertyName("map_of_map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_property");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);            writer.WritePropertyName("map_with_undeclared_properties_string");
-            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);            writer.WritePropertyName("anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.EmptyMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapOfMapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_property");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapProperty, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_1");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype1, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_2");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype2, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_anytype_3");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesAnytype3, jsonSerializerOptions);
+            writer.WritePropertyName("map_with_undeclared_properties_string");
+            JsonSerializer.Serialize(writer, additionalPropertiesClass.MapWithUndeclaredPropertiesString, jsonSerializerOptions);
+            writer.WritePropertyName("anytype_1");
             JsonSerializer.Serialize(writer, additionalPropertiesClass.Anytype1, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/ArrayTest.cs

@@ -192,8 +192,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ArrayTest arrayTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_array_of_integer");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);            writer.WritePropertyName("array_array_of_model");
-            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);            writer.WritePropertyName("array_of_string");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfInteger, jsonSerializerOptions);
+            writer.WritePropertyName("array_array_of_model");
+            JsonSerializer.Serialize(writer, arrayTest.ArrayArrayOfModel, jsonSerializerOptions);
+            writer.WritePropertyName("array_of_string");
             JsonSerializer.Serialize(writer, arrayTest.ArrayOfString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/Drawing.cs

@@ -197,9 +197,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Drawing drawing, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("mainShape");
-            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);            writer.WritePropertyName("shapes");
-            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);            writer.WritePropertyName("nullableShape");
-            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);            writer.WritePropertyName("shapeOrNull");
+            JsonSerializer.Serialize(writer, drawing.MainShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapes");
+            JsonSerializer.Serialize(writer, drawing.Shapes, jsonSerializerOptions);
+            writer.WritePropertyName("nullableShape");
+            JsonSerializer.Serialize(writer, drawing.NullableShape, jsonSerializerOptions);
+            writer.WritePropertyName("shapeOrNull");
             JsonSerializer.Serialize(writer, drawing.ShapeOrNull, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/EnumArrays.cs

@@ -310,6 +310,7 @@ namespace Org.OpenAPITools.Model
         {
             writer.WritePropertyName("array_enum");
             JsonSerializer.Serialize(writer, enumArrays.ArrayEnum, jsonSerializerOptions);
+
             var justSymbolRawValue = EnumArrays.JustSymbolEnumToJsonValue(enumArrays.JustSymbol);
             if (justSymbolRawValue != null)
                 writer.WriteString("just_symbol", justSymbolRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/FileSchemaTestClass.cs

@@ -175,7 +175,8 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FileSchemaTestClass fileSchemaTestClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("file");
-            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);            writer.WritePropertyName("files");
+            JsonSerializer.Serialize(writer, fileSchemaTestClass.File, jsonSerializerOptions);
+            writer.WritePropertyName("files");
             JsonSerializer.Serialize(writer, fileSchemaTestClass.Files, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/FormatTest.cs

@@ -587,11 +587,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, FormatTest formatTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("binary");
-            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);            writer.WritePropertyName("byte");
-            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
+            JsonSerializer.Serialize(writer, formatTest.Binary, jsonSerializerOptions);
+            writer.WritePropertyName("byte");
+            JsonSerializer.Serialize(writer, formatTest.VarByte, jsonSerializerOptions);
+            writer.WriteString("date", formatTest.Date.ToString(DateFormat));
             writer.WriteString("dateTime", formatTest.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("decimal");
-            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);            writer.WriteNumber("double", formatTest.VarDouble);
+            JsonSerializer.Serialize(writer, formatTest.VarDecimal, jsonSerializerOptions);
+            writer.WriteNumber("double", formatTest.VarDouble);
             writer.WriteNumber("float", formatTest.VarFloat);
             writer.WriteNumber("int32", formatTest.Int32);
             writer.WriteNumber("int64", formatTest.Int64);

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MapTest.cs

@@ -275,9 +275,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, MapTest mapTest, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("direct_map");
-            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);            writer.WritePropertyName("indirect_map");
-            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);            writer.WritePropertyName("map_map_of_string");
-            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);            writer.WritePropertyName("map_of_enum_string");
+            JsonSerializer.Serialize(writer, mapTest.DirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("indirect_map");
+            JsonSerializer.Serialize(writer, mapTest.IndirectMap, jsonSerializerOptions);
+            writer.WritePropertyName("map_map_of_string");
+            JsonSerializer.Serialize(writer, mapTest.MapMapOfString, jsonSerializerOptions);
+            writer.WritePropertyName("map_of_enum_string");
             JsonSerializer.Serialize(writer, mapTest.MapOfEnumString, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs

@@ -222,7 +222,8 @@ namespace Org.OpenAPITools.Model
         {
             writer.WriteString("dateTime", mixedPropertiesAndAdditionalPropertiesClass.DateTime.ToString(DateTimeFormat));
             writer.WritePropertyName("map");
-            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
+            writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
             writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/NullableClass.cs

@@ -318,10 +318,14 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, NullableClass nullableClass, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("array_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("object_items_nullable");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);            writer.WritePropertyName("array_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("array_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("object_items_nullable");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectItemsNullable, jsonSerializerOptions);
+            writer.WritePropertyName("array_and_items_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ArrayAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("array_nullable_prop");
             JsonSerializer.Serialize(writer, nullableClass.ArrayNullableProp, jsonSerializerOptions);
+
             if (nullableClass.BooleanProp != null)
                 writer.WriteBoolean("boolean_prop", nullableClass.BooleanProp.Value);
             else
@@ -348,8 +352,10 @@ namespace Org.OpenAPITools.Model
                 writer.WriteNull("number_prop");
 
             writer.WritePropertyName("object_and_items_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);            writer.WritePropertyName("object_nullable_prop");
-            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);            writer.WriteString("string_prop", nullableClass.StringProp);
+            JsonSerializer.Serialize(writer, nullableClass.ObjectAndItemsNullableProp, jsonSerializerOptions);
+            writer.WritePropertyName("object_nullable_prop");
+            JsonSerializer.Serialize(writer, nullableClass.ObjectNullableProp, jsonSerializerOptions);
+            writer.WriteString("string_prop", nullableClass.StringProp);
         }
     }
 }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/ObjectWithDeprecatedFields.cs

@@ -211,8 +211,10 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, ObjectWithDeprecatedFields objectWithDeprecatedFields, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("bars");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);            writer.WritePropertyName("deprecatedRef");
-            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.Bars, jsonSerializerOptions);
+            writer.WritePropertyName("deprecatedRef");
+            JsonSerializer.Serialize(writer, objectWithDeprecatedFields.DeprecatedRef, jsonSerializerOptions);
+            writer.WriteNumber("id", objectWithDeprecatedFields.Id);
             writer.WriteString("uuid", objectWithDeprecatedFields.Uuid);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/Pet.cs

@@ -327,10 +327,12 @@ namespace Org.OpenAPITools.Model
         public void WriteProperties(ref Utf8JsonWriter writer, Pet pet, JsonSerializerOptions jsonSerializerOptions)
         {
             writer.WritePropertyName("category");
-            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);            writer.WriteNumber("id", pet.Id);
+            JsonSerializer.Serialize(writer, pet.Category, jsonSerializerOptions);
+            writer.WriteNumber("id", pet.Id);
             writer.WriteString("name", pet.Name);
             writer.WritePropertyName("photoUrls");
             JsonSerializer.Serialize(writer, pet.PhotoUrls, jsonSerializerOptions);
+
             var statusRawValue = Pet.StatusEnumToJsonValue(pet.Status);
             if (statusRawValue != null)
                 writer.WriteString("status", statusRawValue);

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/User.cs

@@ -339,13 +339,16 @@ namespace Org.OpenAPITools.Model
             writer.WriteNumber("id", user.Id);
             writer.WriteString("lastName", user.LastName);
             writer.WritePropertyName("objectWithNoDeclaredProps");
-            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);            writer.WriteString("password", user.Password);
+            JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredProps, jsonSerializerOptions);
+            writer.WriteString("password", user.Password);
             writer.WriteString("phone", user.Phone);
             writer.WriteNumber("userStatus", user.UserStatus);
             writer.WriteString("username", user.Username);
             writer.WritePropertyName("anyTypeProp");
-            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);            writer.WritePropertyName("anyTypePropNullable");
-            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypeProp, jsonSerializerOptions);
+            writer.WritePropertyName("anyTypePropNullable");
+            JsonSerializer.Serialize(writer, user.AnyTypePropNullable, jsonSerializerOptions);
+            writer.WritePropertyName("objectWithNoDeclaredPropsNullable");
             JsonSerializer.Serialize(writer, user.ObjectWithNoDeclaredPropsNullable, jsonSerializerOptions);
         }
     }

samples/client/petstore/csharp/OpenAPIClient-httpclient/api/openapi.yaml

@@ -1036,6 +1036,38 @@ paths:
             type: string
           type: array
         style: form
+      - explode: true
+        in: query
+        name: requiredNotNullable
+        required: true
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: requiredNullable
+        required: true
+        schema:
+          nullable: true
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNotNullable
+        required: false
+        schema:
+          nullable: false
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: notRequiredNullable
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: form
       responses:
         "200":
           description: Success

samples/client/petstore/csharp/OpenAPIClient-httpclient/docs/FakeApi.md

@@ -1357,7 +1357,7 @@ No authorization required
 
 <a id="testqueryparametercollectionformat"></a>
 # **TestQueryParameterCollectionFormat**
-> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context)
+> void TestQueryParameterCollectionFormat (List<string> pipe, List<string> ioutil, List<string> http, List<string> url, List<string> context, string requiredNotNullable, string requiredNullable, string notRequiredNotNullable = null, string notRequiredNullable = null)
 
 
 
@@ -1389,10 +1389,14 @@ namespace Example
             var http = new List<string>(); // List<string> | 
             var url = new List<string>(); // List<string> | 
             var context = new List<string>(); // List<string> | 
+            var requiredNotNullable = "requiredNotNullable_example";  // string | 
+            var requiredNullable = "requiredNullable_example";  // string | 
+            var notRequiredNotNullable = "notRequiredNotNullable_example";  // string |  (optional) 
+            var notRequiredNullable = "notRequiredNullable_example";  // string |  (optional) 
 
             try
             {
-                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
+                apiInstance.TestQueryParameterCollectionFormat(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
             }
             catch (ApiException  e)
             {
@@ -1411,7 +1415,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    apiInstance.TestQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context, requiredNotNullable, requiredNullable, notRequiredNotNullable, notRequiredNullable);
 }
 catch (ApiException e)
 {
@@ -1430,6 +1434,10 @@ catch (ApiException e)
 | **http** | [**List&lt;string&gt;**](string.md) |  |  |
 | **url** | [**List&lt;string&gt;**](string.md) |  |  |
 | **context** | [**List&lt;string&gt;**](string.md) |  |  |
+| **requiredNotNullable** | **string** |  |  |
+| **requiredNullable** | **string** |  |  |
+| **notRequiredNotNullable** | **string** |  | [optional]  |
+| **notRequiredNullable** | **string** |  | [optional]  |
 
 ### Return type