The incoming depth of the queue is the number of incoming messages which have not been received (for example, using QAManagerBase::getMessage).
The outgoing depth of a queue is the number of outgoing messages (including uncommitted) that have not been transmitted to
the server.
If getQueueDepth is called with the LOCAL filter and a queue is specified, it returns the number of unreceived local messages
that are addressed to that queue. If a queue is not specified, it returns the total number of unreceived local messages in
the message store, excluding system messages.