Controls what the server should do if the message cannot be immediately delivered to any consumer.
The Immediate property controls what the server should do if the message can't be immediately delivered to any consumer (either because it cannot be routed to a queue, or because the queues it can be routed to have no active consumers attached to them).
If True, the server will return the message. If False, the server will queue the message if possible, or drop it if not.
This property is not available in the Receiver.