> .. telling the callee how long before the work doesn't matter anymore.

That is interesting - this is actually a feature of JMS, which is employed in Mats: You can say that a Mats Flow is nonPersistent (i.e. "not all that important, really"), and in the same call you can also say how many seconds until timeout.

<https://mats3.io/javadoc/mats3/0.19/api/io/mats3/MatsInitiat...>

This is employed by the MatsFuturizer if you use the "nonEssential" invocation: <https://mats3.io/javadoc/mats3/0.19/modern/io/mats3/util/Mat...>

The point is that if there are too big queues, bunching up even more work on them which will not be processed in time does not make any sense: If the Future on the caller side have already timed out, it makes no sense at all that the callee should process the work and return the answer.