In an unhandled exception notification the exception class in the subject is always UnhandledException. Since this is our exception we know it should always have the source that is really the exception. Reporting the source exception as the cause in the message may make it a little easier to quickly diagnose. Same thought if we want to print just the stack trace for the source and remove the extra context we add as part of handling it.

I still think it good to note the exception was not properly handled rather than just reported.