Consumer.wait() blocks indefinitely

I have a strange issue where Consumer.wait() blocks indefinitely, that is not reproducible using curl.

Basically I'm registering a Consumer for a (rather large) database with a specific since-value (53000000 in my case)

``` python
consumer = Consumer(db)
consumer.wait(self.callback, since=since, include_docs=True)
```

The callback receives and processes three results, and the call then blocks in

``` python
^CTraceback (most recent call last):
File "./manage.py", line 36, in
execute_manager(settings)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 469, in execute_manager
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 392, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 222, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 255, in execute
output = self.handle(*args, **options)
File "/srv/mygpo/mygpo/../mygpo/maintenance/management/changescmd.py", line 59, in handle
self.process(self.db, since)
File "/srv/mygpo/mygpo/../mygpo/maintenance/management/changescmd.py", line 100, in process
consumer.wait(self.callback, since=since, **params)
File "/usr/local/lib/python2.7/dist-packages/couchdbkit-0.6.4-py2.7.egg/couchdbkit/consumer/__init__.py", line 103, in wait
return self._consumer.wait(cb, **params)
File "/usr/local/lib/python2.7/dist-packages/couchdbkit-0.6.4-py2.7.egg/couchdbkit/consumer/sync.py", line 56, in wait
break
File "/usr/local/lib/python2.7/dist-packages/restkit-4.2.1-py2.7.egg/restkit/wrappers.py", line 161, in __exit__
self.close()
File "/usr/local/lib/python2.7/dist-packages/restkit-4.2.1-py2.7.egg/restkit/wrappers.py", line 169, in close
self.body.read()
File "/usr/local/lib/python2.7/dist-packages/http_parser-0.8.1-py2.7-linux-x86_64.egg/http_parser/reader.py", line 33, in readinto
recved = self.http_stream.stream.readinto(buf)
File "/usr/local/lib/python2.7/dist-packages/http_parser-0.8.1-py2.7-linux-x86_64.egg/http_parser/_socketio.py", line 70, in readinto
return _recv_into_sock(self._sock, b)
File "/usr/local/lib/python2.7/dist-packages/http_parser-0.8.1-py2.7-linux-x86_64.egg/http_parser/_socketio.py", line 24, in
_recv_into_sock = lambda sock, buf: sock.recv_into(buf)
KeyboardInterrupt
```

In the CouchDB log the query shows up as

```
[Sun, 03 Mar 2013 12:08:58 GMT] [info] [<0.9352.205>] 127.0.0.1 - - GET /mygpo/_changes?feed=continuous&since=53000000&filter=episode_states%2Fhas_play_events&include_docs=true 200
```

If I repeat the same call with curl, it quickly returns a large number of additional results. I'd therefore rule out an issue on the CouchDB side.

The filter that is used in the query is shown below.

``` javascript
function(doc, req)
{
if(doc.doc_type != "EpisodeUserState")
{
return false;
}

if(doc._deleted == true)
{
return false;
}

if(!doc.actions)
{
return false;
}

function isPlayEvent(action)
{
return action.action == "play";
}

return doc.actions.some(isPlayEvent);
}
```

I've tested and reproduced that with the latest version of couchdbkit, and have since upgraded couchdbkit (as well as restkit and http-parser) to their latest HEADs to rule out any recently fixed issues.

Any suggestions on how to further debug this?