Provide a deduplication strategy

Keen to see something like this, I'd support whatever comes in the official Symfony Messenger project but don't see a need to preempt it.

Could a solution be incubated in a separate project that relies on any MR thats available over there?

Yes, of course, we can do that in a separate project.

Something like sm_deduplicate ?

@dpi I've pushed a new (sandbox) project for sm_deduplicate: https://www.drupal.org/sandbox/lussoluca/3481678 →

Looks good, curious about the range of time and how that works and is documented.

> It seems it will dedupe for a short range of time, but not over say, an hour.

By default, the lock is set to last 5 minutes (300 seconds), but you can configure it when you apply the stamp to the envelope:

new LockStamp(\hash('sha256', \serialize($message)), 3600)

We need to write extensive documentation about how it works.