code: func (rp *ReverseProxy) UseInsecureTransport() {
  	if rp.Transport == nil {
  		transport := &http.Transport{
  			Proxy:               http.ProxyFromEnvironment,
  			Dial:                defaultDialer.Dial,
  			TLSHandshakeTimeout: 10 * time.Second,
  			TLSClientConfig:     &tls.Config{InsecureSkipVerify: true},
  		}
  		if httpserver.HTTP2 {
  			http2.ConfigureTransport(transport)
  		}
  		rp.Transport = transport
  	} else if transport, ok := rp.Transport.(*http.Transport); ok {
  		transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
  		// No http2.ConfigureTransport() here.
  		// For now this is only added in places where
  		// an http.Transport is actually created.
  	}
  }
docs: // UseInsecureTransport is used to facilitate HTTPS proxying
  // when it is OK for upstream to be using a bad certificate,
  // since this transport skips verification.