code: func getDialer(forward proxy.Dialer) proxy.Dialer {
  	allProxy := os.Getenv("all_proxy")
  	if len(allProxy) == 0 {
  		return forward
  	}
  
  	proxyURL, err := url.Parse(allProxy)
  	if err != nil {
  		return forward
  	}
  	prxy, err := proxy.FromURL(proxyURL, forward)
  	if err != nil {
  		return forward
  	}
  
  	noProxy := os.Getenv("no_proxy")
  	if len(noProxy) == 0 {
  		return prxy
  	}
  
  	perHost := proxy.NewPerHost(prxy, forward)
  	perHost.AddFromString(noProxy)
  	return perHost
  }
docs: // This is a rip off of proxy.FromEnvironment with a custom forward dialer