Implements proxy connection for UDP sockets,
        which happens during the bind() phase.

def bind(self, *pos, **kw):
        """
        Implements proxy connection for UDP sockets,
        which happens during the bind() phase.
        """
        proxy_type, proxy_addr, proxy_port, rdns, username, password = self.proxy
        if not proxy_type or self.type != socket.SOCK_DGRAM:
            return _orig_socket.bind(self, *pos, **kw)

        if self._proxyconn:
            raise socket.error(EINVAL, "Socket already bound to an address")
        if proxy_type != SOCKS5:
            msg = "UDP only supported by SOCKS5 proxy type"
            raise socket.error(EOPNOTSUPP, msg)
        super(socksocket, self).bind(*pos, **kw)

        # Need to specify actual local port because
        # some relays drop packets if a port of zero is specified.
        # Avoid specifying host address in case of NAT though.
        _, port = self.getsockname()
        dst = ("0", port)

        self._proxyconn = _orig_socket()
        proxy = self._proxy_addr()
        self._proxyconn.connect(proxy)

        UDP_ASSOCIATE = b"\x03"
        _, relay = self._SOCKS5_request(self._proxyconn, UDP_ASSOCIATE, dst)

        # The relay is most likely on the same host as the SOCKS proxy,
        # but some proxies return a private IP address (10.x.y.z)
        host, _ = proxy
        _, port = relay
        super(socksocket, self).connect((host, port))
        super(socksocket, self).settimeout(self._timeout)
        self.proxy_sockname = ("0.0.0.0", 0)