code: func SetProxy(proxy string) error {
  
  	proxyURL, err := url.ParseRequestURI(proxy)
  
  	if err != nil {
  		return err
  	}
  
  	http.DefaultTransport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
  	LogAccess.Debug("Set http proxy as " + proxy)
  
  	return nil
  }
docs: // SetProxy only working for FCM server.