Client behavior fix when server sends 0 data
Client behavior fix when server sends 0 data

If the server sends zero data, client could hang as it does recv(0).  Fix this by
returning None in that scenario.

jjohnson42/confluent,whowutwut/confluent,xcat2/confluent,xcat2/confluent,xcat2/confluent,whowutwut/confluent,xcat2/confluent,jjohnson42/confluent,jjohnson42/confluent,jjohnson42/confluent,whowutwut/confluent,xcat2/confluent,jjohnson42/confluent,whowutwut/confluent