}
}

// Issue 16523
func TestDialContextCancelRace(t *testing.T) {
	oldConnectFunc := connectFunc
	oldGetsockoptIntFunc := getsockoptIntFunc
	oldTestHookCanceledDial := testHookCanceledDial
	defer func() {
		connectFunc = oldConnectFunc
		getsockoptIntFunc = oldGetsockoptIntFunc
		testHookCanceledDial = oldTestHookCanceledDial
	}()

	ln := newLocalListener(t, "tcp")
	listenerDone := make(chan struct{})

	origAccept        = poll.AcceptFunc
	origGetsockoptInt = getsockoptIntFunc

	extraTestHookInstallers   []func()
	extraTestHookUninstallers []func()
)

func installTestHooks() {
	socketFunc = sw.Socket
	poll.CloseFunc = sw.Close
	connectFunc = sw.Connect
	listenFunc = sw.Listen
	poll.AcceptFunc = sw.Accept
	getsockoptIntFunc = sw.GetsockoptInt

	for _, fn := range extraTestHookInstallers {
		fn()

	socketFunc        func(int, int, int) (int, error)  = syscall.Socket
	connectFunc       func(int, syscall.Sockaddr) error = syscall.Connect
	listenFunc        func(int, int) error              = syscall.Listen
	getsockoptIntFunc func(int, int, int) (int, error)  = syscall.GetsockoptInt

		// details.
		if err := fd.pfd.WaitWrite(); err != nil {
			select {
			case <-ctxDone:
				return nil, mapErr(ctx.Err())
			default:
			}
			return nil, err
		}
		nerr, err := getsockoptIntFunc(fd.pfd.Sysfd, syscall.SOL_SOCKET, syscall.SO_ERROR)
		if err != nil {
			return nil, os.NewSyscallError("getsockopt", err)
		}
		switch err := syscall.Errno(nerr); err {