rumqttc: TopicNotUtf8 error causes disconnection when subscribing to system topics

[relufi]

I encountered an issue when using rumqttc to subscribe to the system topic "$SYS/brokers/+/clients/+/connected"(my mqtt server is emqx), which is used to monitor client connection events. Some clients have non-UTF-8 encoded IDs, and when such a client connects, rumqttc throws a TopicNotUtf8 error. This causes rumqttc to disconnect and reconnect automatically.

The frequent disconnections lead to unstable connections and message loss in my application. I believe that instead of disconnecting upon encountering a TopicNotUtf8 error, rumqttc should either:

Ignore the invalid topic and continue running normally.

Handle the error in a way that does not cause a reconnection.

Would it be possible to improve the error handling in this scenario? Thank you!