i also ran into the problem of cyclic dependencies. i know if i would
call gc.collect() the problem would be solved, but calling gc.collect()
takes a long time. 

the problem is the cyclic dependency with
r.recv=r.read

i have fixed it localy by wrapping the addinfourl into a new class (i
called it addinfourlFixCyclRef) and overloading the close method, and
within the close method set the recv to none again.

class addinfourlFixCyclRef(addinfourl):
    def close(self):
        if self.fp is not None and hasattr(self.fp, "_sock"):
            self.fp._sock.recv = None
        addinfourl.close(self)

....

        r.recv = r.read
        fp = socket._fileobject(r, close=True)

        resp = addinfourlFixCyclRef(fp, r.msg, req.get_full_url())


and when i call .close() from the response it just works. Unluckily i
had to patch even more in case there is an exception called.
For the whole fix see the attachment