Asynchronous work

Tier: on demand — nothing in this skill applies until an operation genuinely leaves the request. The first section decides whether it does; if not, close this file.

Messenger, Mailer and Scheduler. One transport, three rules.

First: does this need to be asynchronous at all?

An operation becomes a message when the user does not need the result. That is the whole test. Not "it is slow": slow work the user is waiting for is still slow when a worker does it, it has just moved somewhere nobody is watching, and now the user gets a success page for something that has not happened yet.