Container.connect does not load json config if url is specified

The documentation for Container.connect states that you can load a json config file, and that some options are only configurable via that config file, however when trying to use this file to specify some otherwise non-configurable options for my application I noticed that there didn't seem to be any effect, in fact even a malformed json file did not cause any errors.  Looking at the code it appears that _get_default_config in _reactor.py is only called if a url is not provided.