每隔5秒调用一次MQClientInstance.persistAllConsumerOffset()方法将消费进度向Broker同步。遍历MQClientInstance.consumerTable: ConcurrentHashMap<String/*group */, MQConsumerInner>变量。对于PushConsumer端和PullConsumer端,处理逻辑是一样的,以DefaultMQPushConsumerImpl为例,调用DefaultMQPushConsumerImpl.persistConsumerOffset()方法。每隔5秒调用一次MQClientInstance.persistAllConsumerOffs