COMPAT: Need to read Bytes on Python
Reading from s3 on Python 3 returns a Bytes object.

Yep, thanks.

I just tested this out, and Py3 needs it. I'm not sure this can be tested well with CI... but could you add a release note in `doc/source/whatsnew/v0.16.0.txt`?
 Sure. Done.
 Thanks.
