I bumped into this trying to do:

>>> conn = client.connect(...)
>>> result = conn.jobs.export('search ...', output_mode='csv')
>>> result.readline()
'"'

The problem is the 1 byte peek followed by a one byte read here:

https://hg.python.org/cpython/file/v2.7.5/Modules/_io/iobase.c#l466

This results in an attempt to read 0 bytes from the HTTPResponse in result._response, which ends up hitting this code path:

https://hg.python.org/cpython/file/v2.7.5/Lib/httplib.py#l567

We ask for 0 bytes, and sure enough, we get 0 bytes, but httplib sees this as "no data left" and closes the connection.

I couldn't figure out how best to test this, or indeed, how to run the test suite in such a way that the existing tests on HEAD of master all passed before I started work. But, functional testing has shown this to work.