def handle_call(self, body, message):
        try:
            r = self._DISPATCH(body, ticket=message.properties['reply_to'])
        except self.Next:
            # don't reply, delegate to other agents.
            pass
        else:
            self.reply(message, r)
Advance relavent states for next slice.
dataset/ETHPy150Open celery/cell/cell/actors.py/Actor.handle_call--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/model.py/TransientShardState.advance_for_next_slice