const (
	MethodGet     = "GET"
	MethodHead    = "HEAD"
	MethodPost    = "POST"
	MethodPut     = "PUT"
	MethodPatch   = "PATCH" // RFC 5789
	MethodDelete  = "DELETE"
	MethodConnect = "CONNECT"
	MethodOptions = "OPTIONS"
	MethodTrace   = "TRACE"

	h2.AllowHTTP = true
	h2Server := &http2.Server{}
	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method == http.MethodConnect {
			if handleConnect(w, r) {
				return
			}
		} else {
			log.Errorf("non-CONNECT: %v", r.Method)
			w.WriteHeader(http.StatusMethodNotAllowed)
		}
	})
	hs := &http.Server{

	b, err := httputil.DumpRequest(req, false)
	if err != nil {
		h.t.Logf("Failed to dump request, host=%s: %v", req.Host, err)
	} else {
		h.t.Logf("Proxy Request: %s", string(b))
	}

	if req.Method != http.MethodConnect {
		h.httpProxy.ServeHTTP(rw, req)
		return
	}

	// CONNECT proxy

	sconn, err := net.Dial("tcp", req.Host)
	if err != nil {
		h.t.Logf("Failed to dial proxy backend, host=%s: %v", req.Host, err)

	// * Less visibility into i/o
	// * http will call conn.Close, which will close before we want to (finished writing response).
	pr, pw := io.Pipe()
	r, err := http.NewRequest(http.MethodConnect, url, pr)
	if err != nil {
		return fmt.Errorf("new request: %v", err)
	}
	r.Host = address

	// Initiate CONNECT.
	log.Infof("initiate CONNECT to %v via %v", r.Host, url)