nethttp/response_recorder.go
func (res *ResponseRecorder) WriteHeader(statusCode int) {
	if res.statusCode == 0 { // set it only if not setted already, we don't want logs about multiple sends
		res.statusCode = statusCode
		res.underline.WriteHeader(statusCode)
	}

}
func (res *ResponseRecorder) WriteHeader(statusCode int) {
	if res.statusCode == 0 { // set it only if not setted already, we don't want logs about multiple sends
		res.statusCode = statusCode
		res.underline.WriteHeader(statusCode)
	}

}
// WriteHeader sends an HTTP response header with status code.
// If WriteHeader is not called explicitly, the first call to Write
// will trigger an implicit WriteHeader(http.StatusOK).
// Thus explicit calls to WriteHeader are mainly used to
// send error codes.