环境：EMQX开源版本5.4.0
客户端通过共享订阅的方式，订阅了系统主题：$SYS/brokers/+/clients/+/subscribed
用于监听客户端的订阅事件
有两个订阅组：A 和 B 同时订阅
共享策略采用的是：round_robin_per_group
实际运行时发现，两个共享组内部经常收到重复的事件消息，比如一个订阅成功后，会收到多条事件通知。
请问出现这种情况可能是什么原因呢？
- 通过 Dashboard 检查一下订阅列表看是否有问题。
- 打开 emqx 的日志看看消息转发的流程。https://www.emqx.io/docs/zh/latest/observability/log.html#日志
- 通过dashboard查看，订阅确实没有问题，每个客户端都只通过共享订阅，订阅了订阅消息
- 追踪了一下客户端日志，发现重复的事件中，事件内部的timestamp相差都是1ms，而且是同一个emqx节点分发到不同的客户端中，如：
emqx@11.186.55.163 →
client_20: 1712028537184
client_18: 1712028537183
client_17: 1712028537182
2024-04-02T11:28:57.184682+08:00 [MQTT] client_20@11.181.209.13:47789 msg: mqtt_packet_sent, packet: PUBLISH(Q0, R0, D0, Topic=push/event/client_online, PacketId=undefined, Payload={"username":"1000100_47545100885a370c9e439eea100011f14a18","topic":"push/1000100/1000100_47545100885a370c9e439eea100011f14a18","timestamp":1712028537184,"sub_props":{"User-Property":{}},"qos":0,"peerhost":"183.252.240.213","node":"emqx@11.186.55.163","metadata":{"rule_id":"client_event_online"},"event":"session.subscribed","clientid":"1000100_47545100885a370c9e439eea100011f14a18"})
2024-04-02T11:28:57.183916+08:00 [MQTT] client_18@11.181.209.13:47783 msg: mqtt_packet_sent, packet: PUBLISH(Q0, R0, D0, Topic=push/event/client_online, PacketId=undefined, Payload={"username":"1000100_47545100885a370c9e439eea100011f14a18","topic":"push/1000100/1000100_47545100885a370c9e439eea100011f14a18","timestamp":1712028537183,"sub_props":{"User-Property":{}},"qos":0,"peerhost":"183.252.240.213","node":"emqx@11.186.55.163","metadata":{"rule_id":"client_event_online"},"event":"session.subscribed","clientid":"1000100_47545100885a370c9e439eea100011f14a18"})
2024-04-02T11:28:57.182877+08:00 [MQTT] client_17@11.181.209.13:48725 msg: mqtt_packet_sent, packet: PUBLISH(Q0, R0, D0, Topic=push/event/client_online, PacketId=undefined, Payload={"username":"1000100_47545100885a370c9e439eea100011f14a18","topic":"push/1000100/1000100_47545100885a370c9e439eea100011f14a18","timestamp":1712028537182,"sub_props":{"User-Property":{}},"qos":0,"peerhost":"183.252.240.213","node":"emqx@11.186.55.163","metadata":{"rule_id":"client_event_online"},"event":"session.subscribed","clientid":"1000100_47545100885a370c9e439eea100011f14a18"})
是否跟共享订阅的策略有关系呢