Preferred logging mechanism?

Summary

Where can I log custom messages during interview?

Content

Hi all,

We need to be able to write to a log somewhere during the interview process.  I know the is the hub message log, however I don't think that is able to be written to by custom code.

We already have a lot of javascript in our interviews so it would be trivial to add a little more, but I don't know where best to log messages.  Is there a place within Intelligent Advisor?

I've seen one suggestion to create a Service Cloud custom object and log to that, but I'd like to avoid calling out to an external party if at all possible.