Handle all items in a deque. Can call asynchronous handlers.

        :param deq: a deque of items to be handled by this router
        :param limit: the number of items in the deque to the handled
        :return: the number of items handled successfully

async def handleAll(self, deq: deque, limit=None) -> int:
        """
        Handle all items in a deque. Can call asynchronous handlers.

        :param deq: a deque of items to be handled by this router
        :param limit: the number of items in the deque to the handled
        :return: the number of items handled successfully
        """
        count = 0
        while deq and (not limit or count < limit):
            count += 1
            item = deq.popleft()
            await self.handle(item)
        return count