def mode_receive(self, request):
        """
        This is called by render_POST when the client is telling us
        that it is ready to receive data as soon as it is available.
        This is the basis of a long-polling (comet) mechanism: the
        server will wait to reply until data is available.

        Args:
            request (Request): Incoming request.

        """
        suid = request.args.get('suid', ['0'])[0]
        if suid != '0':
            return ''

        dataentries = self.databuffer.get(suid, [])
        if dataentries:
            return dataentries.pop(0)
        request.notifyFinish().addErrback(self._responseFailed, suid, request)
        if suid in self.requests:
            self.requests[suid].finish()  # Clear any stale request.
        self.requests[suid] = request
        return server.NOT_DONE_YET
dataset/ETHPy150Open evennia/evennia/evennia/server/portal/webclient.py/WebClient.mode_receive/operator `==` -> `!=`