adhearsion/adhearsion — pull request #524 by vangberg (2014-11-14 19:23:57+00:00)
Title: [CS] Invoke pre_join callback with #call instead of #[]

Generally it seems like procs are invoked with `#call` in Adhearsion,
and as such, the `#[]` threw me off when I was figuring out some
`pre_join`-related logic.

As far as I can tell, there is no reason for using `#[]`, and so
consistency should be favored.