response_writer.go
func NewResponseWriter(method string, rw http.ResponseWriter) ResponseWriter {
	return &responseWriter{method, rw, 0, 0, nil}
}
func NewResponseWriter(method string, rw http.ResponseWriter) ResponseWriter {
	return &responseWriter{method, rw, 0, 0, nil}
}
// NewResponseWriter creates a ResponseWriter that wraps an http.ResponseWriter