code: func DefaultTransport() *http.Transport {
  	return &http.Transport{
  		Proxy: http.ProxyFromEnvironment,
  		DialContext: (&net.Dialer{
  			Timeout:   30 * time.Second,
  			KeepAlive: 30 * time.Second,
  		}).DialContext,
  		TLSHandshakeTimeout: 10 * time.Second,
  		DisableKeepAlives:   false,
  		MaxIdleConnsPerHost: 1,
  	}
  }
docs: // DefaultTransport returns a new http.Transport with similar default
  // values to http.DefaultTransport. Do not use this for transient transports as
  // it can leak file descriptors over time. Only use this for transports that
  // will be re-used for the same host(s).