Used to indicate whether the message will be enqueued as buffered or persistent and to specify what kinds of messages should be dequeued.
property DeliveryMode: TQueueDeliveryMode default qdmPersistent;
Use the DeliveryMode property to indicate whether the message will be enqueued as buffered or persistent when enqueueing it, and to specify what kinds of messages should be dequeued (buffered, persistent or both), when dequeueing messages. qdmPersistentOrBuffered value can be set only when dequeuing a message.