Lev

There are 5 streams in the MQTT implementation; 2 are involved in every client session/message`$MQTT_sess`, `$MQTT_msgs`; `$MQTT_rmsgs` stores the MQTT retained messages, `$MQTT_qos2in`, `$MQTT_out` are used exclusively to process QOS2...

@rolflussi please feel free to open a PR on this! Will be much appreciated!

@thierryba the connection event callbacks are indeed asynchronous, and may be called after `natsConnection_Destroy` has returned. I question the need to pass the `MessagingController`'s `this` pointer as the closure context...

@thierryba, understood. I could easily add `natsOptions_SetNoCallbacksFromDestroy` to disable the callbacks from the destructor, and leaving you to add the cleanup code there explicitly. I'd like to point out that...

@thierryba I think that adding `natsOptions_SetNoCallbacksFromDestroy` could be quite confusing. I am still unclear on why do you need to pass the `MessagingController` pointer to the connection callbacks. Can `MessagingController`...

Ok, after running into this myself while fixing https://github.com/nats-io/nats.c/pull/771, I think what really needs to happen is natsConnection_Drain should wait for all async errors to be processed, much like it...

@Dhruvan1 would it be possible to provide a little more details, and perhaps the scripts used? Was this tested against a single server or a cluster?

@kozlovic ACK that it is way too early to review, and I am focused on other things for the time being anyway. I marked you to get your "FYI"-level attention,...