If no messages have been delivered to the client runtime for the QueueReceiver
at the time receiveNoWait() is called, the method will return immediately with
'null'.
It does take a finite amount of time for the broker to 'accept' and 'route'
messages to Consumers. So, a call to receiveNoWait() right after a message is
'produced' will most probably result in *no* Message being received.