If you want to observe the size and not assert on it, :observer is specifically for this. :observer.start() will open the Observer WX GUI, go to the processes tab and you can sort on the MsgQ column. Right-clicking will allow you to get a dump of the current messages, but the Processes tab will refresh itself every so often, so you can use it to monitor for message queues growing, which usually means you have a bug with an unmatched message. I have found at least 3 bugs in production using only the MsgQ column and clicking to sort it. It is super useful.
