def __init__(self, port, proto, interface='', maxPacketSize=8192,
                 reactor=None):
        """
        Initialize with a numeric port to listen on.
        """
        self.port = port
        self.protocol = proto
        self.readBufferSize = maxPacketSize
        self.interface = interface
        self.setLogStr()
        self._connectedAddr = None
        self._setAddressFamily()

        abstract.FileHandle.__init__(self, reactor)

        skt = socket.socket(self.addressFamily, self.socketType)
        addrLen = _iocp.maxAddrLen(skt.fileno())
        self.addressBuffer = bytearray(addrLen)
        # WSARecvFrom takes an int
        self.addressLengthBuffer = bytearray(struct.calcsize('i'))

        Initialize with a numeric port to listen on.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/iocpreactor/udp.py