coreos/rocket — pull request #231 by jzelinskie (2014-12-07 22:59:06+00:00)
Title: cas: write download progress to stdout

This introduces ProgressReader, a io.Reader proxy that keeps track of
the bytes read and fires off a callback with the current state.

Fixes #208

---

There are lots of different ways of doing this. I don't know if there is any precedent for writing to stdout yet, but this seems okay for now.