adding the exception RecordNotFound to UUID find
Implemented enqueue_at for ActiveJob's Backburner adapter
Active Job guide: Add info about queue_name prefix and clarity supporter features
Merge pull request #16642 from cristianbica/aj-doc-queue-name-prefix

Active Job Guide: Example of config queue_name_prefix [ci skip]
Merge pull request #16641 from cristianbica/aj-backburner-enqueue-later

Implemented enqueue_at for ActiveJob's Backburner adapter
Merge pull request #16645 from sgrif/sg-perf-regression

Don't calculate in-place changes twice
[ActionMailer] require activejob railtie
Merge pull request #15932 from joseluistorres/issue-11957-uuids

adding the exception RecordNotFound to UUID find #11957
Merge pull request #16598 from seuros/master

[ActionMailer] require activejob railtie
Cache the value of `changed_attributes` when calling `changes_applied`

`changes_applied` calles `changes`, which will call `changed_attributes`
multiple times in a loop. This method actually performs work now, so we
should cache the results while looping over it when we know it cannot
change.