Pull model support

我看了你的代码,发现只有push消费模式,虽然另一个库包含pull模式,但是已经不维护并更新到这个包下了,希望能完善这个包

Start by reading the existing push consumption implementation in this Python client and compare it with the pull mode from the other, unmaintained library mentioned in the issue. Identify the client entry points and behavior that would need to support pull consumption. Done means pull-mode consumption is integrated into this package and covered by appropriate tests.

由索引模型根据 Issue 内容生成。