twitter/scalding — pull request #875 by amatsukawa (2014-05-15 01:07:31+00:00)
Title: add stepListner register support in Scalding

Scalding already has support for registering `cascading.flow.FlowListeners` to flows. Add similar support for registering `cascading.flow.FlowStepListners`.

Needed in https://github.com/twitter/ambrose, for example.