forked from loafle/openapi-generator-original
* [dart][dart-dio] Refactor API template * first construct a `RequestOptions` instance with all parameters etc. inline * then construct and serialize the body data * then send the request and await the response * then deserialize the response * always use the `specifiedType` for built_value (de)serialization instead of a mix of ways (this does the same as finding the serializer directly) * use indent of 2 spaces (as per Dart convention) * prefix all local variables to prevent name clashes with parameters * Add tests that (de)serialize collections and add API key header