Start async adapters after_initialize instead of once Active Job and Active Record are loaded and Rails initialized?

[bensheldon]

The problem with when Async Adapters are started has overall been vexing. Problems like #930 have been reported, and I experienced this in #1294.

The unfortunate part of this is that Rails.application.initialized? isn't hookable and all after_initialize callbacks happen before tha becomes true.

The major change here is that GoodJob is now initialized before Puma finishes booting, which means that sometimes GoodJob will run before the Puma banner is output.

Why did this work before? In some apps, ActiveRecord::Base would not be loaded during initialization. Then, during the first web request and after initialized? the hook would be called and GoodJob's async adapters would start.

Why didn't this work before? In other apps, ActiveRecord::Base would be loaded during initialization and before initialized?. This led to GoodJob's async adapters never being started.