response_wrapper.go
func NewResponseWrapper(w http.ResponseWriter) *ResponseWrapper {
	return &ResponseWrapper{ResponseRecorder: httptest.NewRecorder(), writer: w}
}
func NewResponseWrapper(w http.ResponseWriter) *ResponseWrapper {
	return &ResponseWrapper{ResponseRecorder: httptest.NewRecorder(), writer: w}
}
// NewResponseWrapper creates a new wrapper. The passed http.ResponseWriter is
// used in case the wrapper needs to be hijacked.