EasyProgramming

[Bug] When sending a message with qos=2, according to the MQTT 3.1.1 protocol, MQTTX should first store the message locally and then proceed with sending.

6

在发送qos=2的消息，根据mqtt3.1.1的协议，mqttx应该先把该消息存储在本地，然后进行发送

Prefix scan didn't work well when enabling the cluster mode

8

### Search before asking - [X] I had searched in the [issues](https://github.com/apache/kvrocks/issues) and found no similar issues. ### Version centos 7.9 Kvrocks was running with two cluster nodes and slot...