'Async version of get_stats().
Returns:
A UserRPC instance whose get_result() method returns None if
there was a network error, otherwise a dict just like
get_stats() returns.'

def get_stats_async(self, rpc=None):

    request = MemcacheStatsRequest()
    self._add_app_id(request)
    response = MemcacheStatsResponse()
    return self._make_async_call(rpc, 'Stats', request, response, self.__get_stats_hook, None)
