rails/rails — pull request #4417 by bogdan (2012-01-12 08:49:10+00:00)
Title: AS::Callbacks: remove unused runner

Based on discussion under #4305 and benchmark: https://github.com/rails/rails/issues/4305#issuecomment-3395384

Reapply the "remove runner" commit with additional change for AR `after_initialize` callbacks and fix Guides examle.

#4305 could be closed I believe.

cc @josevalim