func TestReadNonblockingFd(t *testing.T) {
	switch runtime.GOOS {
	case "windows":
		t.Skip("Windows doesn't support SetNonblock")
	}
	if os.Getenv("GO_WANT_READ_NONBLOCKING_FD") == "1" {
		fd := syscallDescriptor(os.Stdin.Fd())
		syscall.SetNonblock(fd, true)
		defer syscall.SetNonblock(fd, false)
		_, err := os.Stdin.Read(make([]byte, 1))
		if err != nil {