add some form of "instrumentation"

[kellyredding]

thought came from reading this:
http://www.railstips.org/blog/archives/2013/04/18/let-nunes-do-it/

Rails publishes "events" as stuff happens. Counter events and timing events. We should think about doing something similar.

• maybe make it a separate thing so you can add it if you want but not have it forced on you
• maybe a sep thing like "nunes" that captures events and publishes to a stats service. maybe make the core thing generic so you can write any number of "publish adapters".

Just some thoughts. /cc @jcredding