diff --git a/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs
new file mode 100644
index 00000000000..0c9ebe09457
--- /dev/null
+++ b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs
@@ -0,0 +1,23 @@
+//------------------------------------------------------------------------------
+//
+// This code was generated by a tool.
+// Runtime Version:4.0.30319.42000
+//
+// Changes to this file may cause incorrect behavior and will be lost if
+// the code is regenerated.
+//
+//------------------------------------------------------------------------------
+
+using System;
+using System.Reflection;
+
+[assembly: System.Reflection.AssemblyCompanyAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
+[assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
+[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]
+[assembly: System.Reflection.AssemblyProductAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyTitleAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]
+
+// Generated by the MSBuild WriteCodeFragment class.
+
diff --git a/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache
new file mode 100644
index 00000000000..217033a3db2
--- /dev/null
+++ b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache
@@ -0,0 +1 @@
+19e887ae0fddb9fd03c4341951ee9077703a652f
diff --git a/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs
new file mode 100644
index 00000000000..0c9ebe09457
--- /dev/null
+++ b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfo.cs
@@ -0,0 +1,23 @@
+//------------------------------------------------------------------------------
+//
+// This code was generated by a tool.
+// Runtime Version:4.0.30319.42000
+//
+// Changes to this file may cause incorrect behavior and will be lost if
+// the code is regenerated.
+//
+//------------------------------------------------------------------------------
+
+using System;
+using System.Reflection;
+
+[assembly: System.Reflection.AssemblyCompanyAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
+[assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
+[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]
+[assembly: System.Reflection.AssemblyProductAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyTitleAttribute("Org.OpenAPITools.Test")]
+[assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]
+
+// Generated by the MSBuild WriteCodeFragment class.
+
diff --git a/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache
new file mode 100644
index 00000000000..217033a3db2
--- /dev/null
+++ b/CI/samples.ci/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools.Test/obj/Debug/netcoreapp2.0/Org.OpenAPITools.Test.AssemblyInfoInputs.cache
@@ -0,0 +1 @@
+19e887ae0fddb9fd03c4341951ee9077703a652f
diff --git a/CI/samples.ci/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/Org.OpenAPITools.Test.csprojAssemblyReference.cache b/CI/samples.ci/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/Org.OpenAPITools.Test.csprojAssemblyReference.cache
new file mode 100644
index 00000000000..2bd5c20b30f
Binary files /dev/null and b/CI/samples.ci/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools.Test/obj/Debug/Org.OpenAPITools.Test.csprojAssemblyReference.cache differ
diff --git a/modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache b/modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache
index 6e70b0d4a9c..8495fb2e8a0 100644
--- a/modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache
@@ -5,6 +5,7 @@ using System.Collections.Generic;
using System.Globalization;
using System.Text.RegularExpressions;
using System.IO;
+using System.Threading;
{{^netStandard}}
{{^supportsUWP}}
using System.Web;
@@ -235,19 +236,20 @@ namespace {{packageName}}.Client
/// File parameters.
/// Path parameters.
/// Content type.
+ /// Cancellation Token.
/// The Task instance.
public async System.Threading.Tasks.Task