Right now, our exception messages come from the API response in most
cases. But if for any reason there isn't one, we supply a default. I
realized these messages might make it to people's logs so it might be
nice to spend time later making them even more useful.
If a 3rd party client needs to provide a specific HttpContent, we should
allow that in the adapter. Our clients probably shouldn't do this as it
would break encapsulation.
