Summary:
We start off simple here. Python only really has counters so we only implement
counters. There are a lot of options on how to improve this and things get
slightly complicated when we look at the how ecosystem and fb303. Anyway,
simple start.
Reviewed By: quark-zju
Differential Revision: D23577874
fbshipit-source-id: d50f5b2ba302d900b254200308bff7446121ae1d
