Check for non-zero `length` first in `read` loop (#2465)
Check for non-zero `length` first in `read` loop (#2465)

Since both the Python 2 and Python 3 cases need to handle the case of
zero and non-zero length separately, pull this check outside of the
Python 2 or 3 version checks to simplify the code a bit.
mrocklin/distributed,dask/distributed,mrocklin/distributed,mrocklin/distributed,dask/distributed,dask/distributed,blaze/distributed,dask/distributed,blaze/distributed