code: @Post("/custom")
      @ProducesText
      @RequestConverter(CustomRequestConverter.class)
      @ResponseConverter(CustomResponseConverter.class)
      public Response custom(@RequestObject Request request) {
          return new Response(Response.SUCCESS, request.name());
      }
docs: Returns a {@link Response} object which will be converted to a text by the
  {@link CustomResponseConverter}. A {@link Request} is also automatically converted by
  the {@link CustomRequestConverter}.
  
  <p>If you want to specify converters for every methods in a service class, you can specify them
  above the class definition as follows:
  <pre>{@code
  > @RequestConverter(CustomRequestConverter.class)
  > @ResponseConverter(CustomResponseConverter.class)
  > public class MyAnnotatedService {
  >     ...
  > }
  }</pre>