FEATURE REQUEST

1. Please describe the feature you are requesting.
   Add store plugin of RocketMQ.
   
2. Provide any additional detail on your proposed use case for this feature.

• In our company, there are a lot of IOT devices cases. These devices use MQTT protocol and have high availability need for message service.
  To support high availability and scalability, the metadata and data now stored in memory is not enough. A storage plugin of RocketMQ seems necessary.
• Except the consume of MQTT message for IOT devices, we cloud consume message from RocketMQ for data calculate and analyze.

3. Indicate the importance of this issue to you (blocker, must-have, should-have, nice-to-have). Are you currently using any workarounds to address this issue?
   【blocker】
4. If there are some sub-tasks using -[] for each subtask and create a corresponding issue to map to the sub task:

• Support metadata storage of RocketMQ
• Support message storage of RocketMQ