tag control log events so arm can know they're from the same place in the code
Damian told me at the dev mtg that arm is doing regexp backbends to recognize log line duplicates (it will merge all the logs that are basically saying the same thing into one, to make it easier to see what else is going on). If we provide a tag along with the log event, we would make his life easier.
It occurred to me that we could easily add a new "filename:line" param to controller events, since we already know it. (The tag doesn't have to be consistent across runs, just within a run.) We would probably want to declare the tag string opaque, so controllers don't get any ideas about doing more with it.