// enabled, this may be called multiple times.
	ConnectDone func(network, addr string, err error)

	// TLSHandshakeStart is called when the TLS handshake is started. When
	// connecting to an HTTPS site via an HTTP proxy, the handshake happens
	// after the CONNECT request is processed by the proxy.
	TLSHandshakeStart func()

	// TLSHandshakeDone is called after the TLS handshake with either the

pkg net/http, const TrailerPrefix = "Trailer:"
pkg net/http/httptrace, type ClientTrace struct, TLSHandshakeDone func(tls.ConnectionState, error)
pkg net/http/httptrace, type ClientTrace struct, TLSHandshakeStart func()
pkg net/http/httputil, type ReverseProxy struct, ModifyResponse func(*http.Response) error
pkg net/http, method (*Server) Close() error
pkg net/http, method (*Server) Shutdown(context.Context) error

	if d := pconn.t.TLSHandshakeTimeout; d != 0 {
		timer = time.AfterFunc(d, func() {
			errc <- tlsHandshakeTimeoutError{}
		})
	}
	go func() {
		if trace != nil && trace.TLSHandshakeStart != nil {
			trace.TLSHandshakeStart()
		}
		err := tlsConn.HandshakeContext(ctx)
		if timer != nil {
			timer.Stop()
		}
		errc <- err
	}()
	if err := <-errc; err != nil {
		plainConn.Close()

		TLSClientConfig: &tls.Config{
			ServerName: "dns-is-faked.golang",
			RootCAs:    certpool,
		},
	}}

	trace := &httptrace.ClientTrace{
		TLSHandshakeStart: func() { logf("TLSHandshakeStart") },
		TLSHandshakeDone: func(s tls.ConnectionState, err error) {
			logf("TLSHandshakeDone: ConnectionState = %v \n err = %v", s, err)
		},
	}

	req, _ := NewRequest("GET", ts.URL, nil)

		{"ClientTrace.GotConn", Field, 7},
		{"ClientTrace.GotFirstResponseByte", Field, 7},
		{"ClientTrace.PutIdleConn", Field, 7},
		{"ClientTrace.TLSHandshakeDone", Field, 8},
		{"ClientTrace.TLSHandshakeStart", Field, 8},
		{"ClientTrace.Wait100Continue", Field, 7},
		{"ClientTrace.WroteHeaderField", Field, 11},
		{"ClientTrace.WroteHeaders", Field, 7},
		{"ClientTrace.WroteRequest", Field, 7},