}

func (sd *sysDialer) dialUDP(ctx context.Context, laddr, raddr *UDPAddr) (*UDPConn, error) {
	fd, err := dialPlan9(ctx, sd.network, laddr, raddr)
	if err != nil {
		return nil, err
	}
	return newUDPConn(fd), nil
}

const udpHeaderSize = 16*3 + 2*2

type udpHeader struct {
	raddr, laddr, ifcaddr IP
	rport, lport          uint16
}

func (h *udpHeader) Bytes() []byte {

		return nil, err
	}
	switch fd.laddr.(type) {
	case *TCPAddr:
		return newTCPConn(fd, defaultTCPKeepAliveIdle, KeepAliveConfig{}, testPreHookSetKeepAlive, testHookSetKeepAlive), nil
	case *UDPAddr:
		return newUDPConn(fd), nil
	case *IPAddr:
		return newIPConn(fd), nil
	case *UnixAddr:
		return newUnixConn(fd), nil
	}
	fd.Close()
	return nil, syscall.EINVAL
}

func fileListener(f *os.File) (Listener, error) {

			return sd.Dialer.Control(network, address, c)
		}
	}
	fd, err := internetSocket(ctx, sd.network, laddr, raddr, syscall.SOCK_DGRAM, 0, "dial", ctrlCtxFn)
	if err != nil {
		return nil, err
	}
	return newUDPConn(fd), nil
}

func (sl *sysListener) listenUDP(ctx context.Context, laddr *UDPAddr) (*UDPConn, error) {
	var ctrlCtxFn func(ctx context.Context, network, address string, c syscall.RawConn) error

		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)
	if err != nil {
		return nil, err
	}
	switch fd.laddr.(type) {

	}
	n, oobn, err = c.writeMsgAddrPort(b, oob, addr)
	if err != nil {
		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addrPortUDPAddr{addr}, Err: err}
	}
	return
}

func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }

// DialUDP acts like Dial for UDP networks.
//
// The network must be a UDP network name; see func Dial for details.
//