keepalive: be more careful about self._rbuf when calling super impls...
keepalive: be more careful about self._rbuf when calling super impls
In Python 3, HTTPResponse implements read() in terms of readinto(),
which was calling back into our readinto(), which duplicates
self._rbuf if it's not empty. Before calling into super's read(),
ensure self._rbuf is empty.
Inheritance is bad, and undocumented self-use of your public API is
one of many reasons.
Differential Revision:
https://phab.mercurial-scm.org/D4728
