Keep logs and set into debug logging for specific request.

[stolsvik]

Some way to "catch" all log lines that a specific trace emits on all services it passes by, and sticks it on the trace, so that it can be returned to the caller. This would be very nice for a developer that just started working with a code base to get an understanding of what a specific operation entails

The same information could of course be gathered by going to the common log system, but piggybacking on the MatsTrace for this type of exploration would make this simpler.

Indeed, if such a flag was set at initiation, the entire Mats system could effectively go into debug logging for this specific trace - and this information could be returned directly to the browser doing the initiation. (rky inspired)