ActiveMq artemis consumer acknowledgment timeout

[Efstathios Stergou]

Hello,

I am using ActiveMQ Artemis 2.6.1

The setup that I am trying to achieve is:
The consumer gets the messages from the server, does some processing and after 
the processing is completed, it acknowledges the received message. The server 
can then delete the message from the queue.

When I acknowledge the message before processing it everything works fine but 
If I acknowledge after the processing the consumer stops getting messages after 
a while.


Is there a acknowledge timeout setting that I can tweak?

My setup is:
```
ActiveMQClient
  .createServerLocator(conf.artemisUrl)
  .setConsumerWindowSize(-1)
  .setBlockOnAcknowledge(false)
  .setConfirmationWindowSize(1)```

Session creation:
```factory.createSession(true, true, -1))```

asynchronous message delivery:
```consumer.setMessageHandler(handlder)```

and acknowledgement:
```message.individualAcknowledge()```




Thanks.