queuesize can be unreliable

We noticed that sometimes queuesize attribute of some queues are different from the count of messages that exist in the queue. for example queuesize is 9 but there are no messages in the queue. This issue has happened frequently so after investigation we created a test case for the problem.

The test case creates 5 message that each consist of an array of 1 million random bytes. On first run it creates the 5 messages and queuesize becomes 5 as expected. On subsequent runs the messages won't persist on queue but queue size is increased by 5.

Now as a client the code could be improved to prevent such problem but from the perspective of someone who wants to monitor broker states, this is a total failure since she can't know the amount of remaining messages on a queue.