I have run into this same issue. It does violate RFC2616 in section 4.3 "All 1xx (informational), 204 (no content), and 304 (not modified) responses MUST NOT include a message-body. All other responses do include a message-body, although it MAY be of zero length."

The embedded while loop is looking for entity data coming back from the server which will never be seen. In my tests the code dies with an exception. I don't see why anything is being done special for a 100 CONTINUE at all. My fix was to eliminate the code previously quoted and replace it with a single line of code so that it would now look like the code snippet below.

   def begin(self):
        if self.msg is not None:
            # we've already started reading the response
            return
        version, status, reason = self._read_status()
        self.status = status
        self.reason = reason.strip()

Note on providing a patch as stated previously.

Having this restriction on providing a patch is a large deterrent to people. I spent a lot of time myself finding the cause of the issues I was having. I don't really have the time to fix tests and documentation also. I understand the reason for asking, but it certainly is a discouragement to helping when bugs are found.