'Internal helper to schedule an asynchronous RPC.
Args:
rpc: None or a UserRPC object.
method: Method name, e.g. \'Get\'.
request: Request protobuf.
response: Response protobuf.
get_result_hook: None or hook function used to process results
(See UserRPC.make_call() for more info).
user_data: None or user data for hook function.
Returns:
A UserRPC object; either the one passed in as the first argument,
or a new one (if the first argument was None).'

def _make_async_call(self, rpc, method, request, response, get_result_hook, user_data):

    if (rpc is None):
        rpc = create_rpc()
    assert (rpc.service == 'memcache'), repr(rpc.service)
    rpc.make_call(method, request, response, get_result_hook, user_data)
    return rpc
