Issues with using the Asynchronous interface.

[kennetn]

Hi

I am using MQTT via the fluid.paho_mqtt nuget in a C++ application.
The application is multi threaded and I have read the https://eclipse-paho.github.io/paho.mqtt.c/MQTTClient/html/async.html.
I use the MQTTClient_subscribe and MQTTClient_publishMessage functions.
In my MessageArrived callback I put the MQTTClient_message in a que and process that in a separate thread, So the processing is very short.
If I understand the page correctly I can call MQTTClient_publishMessage from different threads as long as I synchronise the access. So the method is called from different threads but never from two thread simultaneously.

Is this correct ?

I am a bit unsure on exactly what this means "This API is not thread safe however - it is not possible to call it from multiple threads without synchronization. You can use the MQTTAsync API for that."
I did not find much documentation on the MQTTAsync API.

Currently I have an issue that when I send 10.000 updates on a topic that I both publish and subscribe some of the updates are not arriving.
I have set the QOS to 2 for both publish and subscribe.
If I use another client to subscribe the topic it looks like all the updates are arriving.

Thanks for any input.

/Kennet