def _transmit_oack(self):
        opts = []
        for key, val in self._options.items():
            fmt = str('%dsx%ds' % (len(key), len(val)))
            opts.append(
                struct.pack(
                    fmt, bytes(key.encode('latin-1')), bytes(
                        val.encode('latin-1')
                    )
                )
            )
        opts.append(b'')
        fmt = str('!H')
        packet = struct.pack(fmt, constants.OPCODE_OACK) + b'\x00'.join(opts)
        self._listener.sendto(packet, self._peer)
        self._stats.packets_sent += 1
Method that deals with sending OACK datagrams on the wire.
dataset/ETHPy150Open facebook/fbtftp/fbtftp/base_handler.py/BaseHandler._transmit_oack