code: func RoundTripperFor(config *restclient.Config) (http.RoundTripper, Upgrader, error) {
  	tlsConfig, err := restclient.TLSConfigFor(config)
  	if err != nil {
  		return nil, nil, err
  	}
  	upgradeRoundTripper := spdy.NewRoundTripper(tlsConfig, true, false)
  	wrapper, err := restclient.HTTPWrappersForConfig(config, upgradeRoundTripper)
  	if err != nil {
  		return nil, nil, err
  	}
  	return wrapper, upgradeRoundTripper, nil
  }
docs: // RoundTripperFor returns a round tripper and upgrader to use with SPDY.