I'd like to note that pulling the callbacks out simplifies the tick method:

https://github.com/koriroys/clockwork/commit/125269bf6e662ae2790f29bce13184469c637180

and that testing the before/after tick callbacks doesn't change so drastically:

https://github.com/koriroys/clockwork/commit/7bf38a624d62b0eac35228e4da63473abe5f451e

It seems to me that the improved readability of the ```tick``` method is worth the tradeoff here.

As far as I can tell, the only reason tick isn't a private method (and the reason it returns events) is for testing purposes, is that right?