if fd.fdmu.rwunlock(true) {
		fd.destroy()
	}
}

// writeLock adds a reference to fd and locks fd for writing.
// It returns an error when fd cannot be used for writing.
func (fd *FD) writeLock() error {
	if !fd.fdmu.rwlock(false) {
		return errClosing(fd.isFile)
	}
	return nil
}

// writeUnlock removes a reference from fd and unlocks fd for writing.

	var v int
	if ifi != nil {
		v = ifi.Index
	}
	err := fd.pfd.SetsockoptInt(syscall.IPPROTO_IPV6, syscall.IPV6_MULTICAST_IF, v)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

func setIPv6MulticastLoopback(fd *netFD, v bool) error {
	err := fd.pfd.SetsockoptInt(syscall.IPPROTO_IPV6, syscall.IPV6_MULTICAST_LOOP, boolint(v))
	runtime.KeepAlive(fd)

	}

	src.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
		switch {
		case fd.IsList():
			o.mergeList(dst.Mutable(fd).List(), v.List(), fd)
		case fd.IsMap():
			o.mergeMap(dst.Mutable(fd).Map(), v.Map(), fd.MapValue())
		case fd.Message() != nil:
			mergeFn, exists := o.customMergeFn[fd.Message().FullName()]
			if exists {
				mergeFn(dst.Mutable(fd).Message(), v.Message())
			} else {

// SetDeadline sets the read and write deadlines associated with fd.
func (fd *FD) SetDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r'+'w')
}

// SetReadDeadline sets the read deadline associated with fd.
func (fd *FD) SetReadDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r')
}

// SetWriteDeadline sets the write deadline associated with fd.
func (fd *FD) SetWriteDeadline(t time.Time) error {

func (fd *FD) SetDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r'+'w')
}

// SetReadDeadline sets the read deadline associated with fd.
func (fd *FD) SetReadDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r')
}

// SetWriteDeadline sets the write deadline associated with fd.
func (fd *FD) SetWriteDeadline(t time.Time) error {

	if err != nil {
		return nil, err
	}

	switch fd.laddr.(type) {
	case *TCPAddr:
		return newTCPConn(fd, defaultTCPKeepAliveIdle, KeepAliveConfig{}, testPreHookSetKeepAlive, testHookSetKeepAlive), nil
	case *UDPAddr:
		return newUDPConn(fd), nil
	}
	return nil, syscall.EPLAN9
}

func fileListener(f *os.File) (Listener, error) {
	fd, err := newFileFD(f)

// Fchown wraps syscall.Fchown.
func (fd *FD) Fchown(uid, gid int) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {
		return syscall.Fchown(fd.Sysfd, uid, gid)
	})
}

// Ftruncate wraps syscall.Ftruncate.
func (fd *FD) Ftruncate(size int64) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {

	return ret, nil
}

func (fd *netFD) init() error {
	// stub for future fd.pd.Init(fd)
	return nil
}

func (fd *netFD) name() string {
	var ls, rs string
	if fd.laddr != nil {
		ls = fd.laddr.String()
	}
	if fd.raddr != nil {
		rs = fd.raddr.String()
	}
	return fd.net + ":" + ls + "->" + rs
}

func (fd *netFD) ok() bool { return fd != nil && fd.ctl != nil }

func (fd *netFD) destroy() {

	if !c.ok() {
		return syscall.EINVAL
	}
	err := c.fd.pfd.RawRead(f)
	runtime.KeepAlive(c.fd)
	if err != nil {
		err = &OpError{Op: "raw-read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return err
}

func (c *rawConn) Write(f func(uintptr) bool) error {
	if !c.ok() {
		return syscall.EINVAL
	}
	err := c.fd.pfd.RawWrite(f)
	runtime.KeepAlive(c.fd)
	if err != nil {

	}
	return nil
}

func setReadBuffer(fd *netFD, bytes int) error {
	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_RCVBUF, bytes)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

func setWriteBuffer(fd *netFD, bytes int) error {
	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_SNDBUF, bytes)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}