7.2.4. Query Sender Capacity

The maximum number of asynchronously sent messages that can be pending acknowledgement at any given time. By default this is UNLIMITED, but it can be changed to constrain the number of unsettled asynchronous calls. An attempt to make a further asynchronous call when the sender is at capacity will block until another sent message is acknowledged by the broker.

The number of asynchronous sends pending acknowledgement from the broker.

The number of additional asynchronous calls that the sender can accept at the moment. This value is available as a property, but can also be computed from sender.capacity - sender.unsettled.