Sam 2b8d4508e5 PERF: stop running background work between requests
Use a dedicated thread to run Scheduler::Defer

This avoids blocking of a worker during operations that require waiting.

In particular uploads risked blocking a unicorn.

This also add a queue "length" that discourse prometheus consumes.
2017-11-23 15:48:47 +11:00
..
2017-10-04 15:59:16 +11:00