code: func (service *Service) Send(ctx context.Context, code int, body interface{}) error {
  	r := ContextResponse(ctx)
  	if r == nil {
  		return fmt.Errorf("no response data in context")
  	}
  	r.WriteHeader(code)
  	return service.EncodeResponse(ctx, body)
  }
docs: // Send serializes the given body matching the request Accept header against the service
  // encoders. It uses the default service encoder if no match is found.