}

// Hijack detaches the [ServerConn] and returns the underlying connection as well
// as the read-side bufio which may have some left over data. Hijack may be
// called before Read has signaled the end of the keep-alive logic. The user
// should not call Hijack while [ServerConn.Read] or [ServerConn.Write] is in progress.
func (sc *ServerConn) Hijack() (net.Conn, *bufio.Reader) {
	sc.mu.Lock()

// Once Write or WriteHeader is called, Hijack returns an error.
// Once Hijack is called, Write, WriteHeader, and Hijack return errors.
type tunnelingResponseWriter struct {
	// w is used to delegate Header(), WriteHeader(), and Write() calls
	w http.ResponseWriter
	// conn is returned from Hijack()
	conn net.Conn
	// mu guards writes
	mu sync.Mutex

			rw = t.Unwrap()
		default:
			return errNotSupported()
		}
	}
}

// Hijack lets the caller take over the connection.
// See the Hijacker interface for details.
func (c *ResponseController) Hijack() (net.Conn, *bufio.ReadWriter, error) {
	rw := c.rw
	for {
		switch t := rw.(type) {
		case Hijacker:
			return t.Hijack()
		case rwUnwrapper:
			rw = t.Unwrap()
		default:
			return nil, nil, errNotSupported()

	assert.Nil(t, bufio, "bufio returned from Hijack() is always nil")
	assert.True(t, trw.hijacked, "hijacked field becomes true after Hijack()")
	assert.False(t, trw.written, "written field stays false after Hijack()")
	// Hijacking after writing to response writer is an error.
	trw = &tunnelingResponseWriter{written: true}
	_, _, err = trw.Hijack()
	assert.Error(t, err, "Hijack after writing to response writer is error")

		ctl := NewResponseController(w)
		c, _, err := ctl.Hijack()
		if mode == http2Mode {
			if err == nil {
				t.Errorf("ctl.Hijack = nil, want error")
			}
			w.Header().Set(header, value)
			return
		}
		if err != nil {
			t.Errorf("ctl.Hijack = _, _, %v, want _, _, nil", err)
			return
		}

	hijacked := make(chan net.Conn)
	ts := NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer close(hijacked)
		hj, ok := w.(http.Hijacker)
		if !ok {
			t.Fatal("failed to hijack")
		}
		c, _, err := hj.Hijack()
		if err != nil {
			t.Fatal(err)
		}
		hijacked <- c
	}))

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()

			w.Header().Set("Connection", "close")
			fmt.Fprintf(w, "Hello.")
		},
		"/hijack": func(w ResponseWriter, r *Request) {
			c, _, _ := w.(Hijacker).Hijack()
			c.Write([]byte("HTTP/1.0 200 OK\r\nConnection: close\r\n\r\nHello."))
			c.Close()
		},
		"/hijack-panic": func(w ResponseWriter, r *Request) {
			c, _, _ := w.(Hijacker).Hijack()
			c.Write([]byte("HTTP/1.0 200 OK\r\nConnection: close\r\n\r\nHello."))
			c.Close()

}

func (tw *baseTimeoutWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
	tw.mu.Lock()
	defer tw.mu.Unlock()

	if tw.timedOut {
		return nil, nil, http.ErrHandlerTimeout
	}

	// the outer ResponseWriter object returned by WrapForHTTP1Or2 implements
	// http.Hijacker if the inner object (tw.w) implements http.Hijacker.
	conn, rw, err := tw.w.(http.Hijacker).Hijack()
	if err == nil {
		tw.hijacked = true

	requestHijacker, ok := w.(http.Hijacker)
	if !ok {
		klog.Errorf("Unable to hijack response writer: %T", w)
		h.Responder.Error(w, req, fmt.Errorf("request connection cannot be hijacked: %T", w))
		return true
	}
	requestHijackedConn, _, err := requestHijacker.Hijack()
	if err != nil {
		klog.Errorf("Unable to hijack response: %v", err)
		h.Responder.Error(w, req, fmt.Errorf("error hijacking connection: %v", err))

	testWriteHeaderAfterWrite(t, http1Mode, true)
}
func testWriteHeaderAfterWrite(t *testing.T, mode testMode, hijack bool) {
	var errorLog lockedBytesBuffer
	cst := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
		if hijack {
			conn, _, _ := w.(Hijacker).Hijack()
			defer conn.Close()
			conn.Write([]byte("HTTP/1.1 200 OK\r\nContent-Length: 6\r\n\r\nfoo"))