if err != nil {
			t.Fatal(err)
		}
		if err := controlRawConn(cc1, ln.Addr()); err != nil {
			t.Fatal(err)
		}

		c, err := Dial(ln.Addr().Network(), ln.Addr().String())
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()

		cc2, err := c.(*TCPConn).SyscallConn()
		if err != nil {
			t.Fatal(err)
		}
		if err := controlRawConn(cc2, c.LocalAddr()); err != nil {
			t.Fatal(err)
		}

func readRawConn(c syscall.RawConn, b []byte) (int, error) {
	return 0, errors.New("not supported")
}

func writeRawConn(c syscall.RawConn, b []byte) error {
	return errors.New("not supported")
}

func controlRawConn(c syscall.RawConn, addr Addr) error {
	return errors.New("not supported")
}

func controlOnConnSetup(network string, address string, c syscall.RawConn) error {
	return nil

		_, operr = syscall.Write(int(s), b)
		if operr == syscall.EAGAIN {
			return false
		}
		return true
	})
	if err != nil {
		return err
	}
	return operr
}

func controlRawConn(c syscall.RawConn, addr Addr) error {
	var operr error
	fn := func(s uintptr) {
		_, operr = syscall.GetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR)
		if operr != nil {
			return
		}

		buf.Buf = &b[0]
		buf.Len = uint32(len(b))
		operr = syscall.WSASend(syscall.Handle(s), &buf, 1, &written, 0, nil, nil)
		return true
	})
	if err != nil {
		return err
	}
	return operr
}

func controlRawConn(c syscall.RawConn, addr Addr) error {
	var operr error
	fn := func(s uintptr) {
		var v, l int32
		l = int32(unsafe.Sizeof(v))