Allow onion services to publish voluntary usage stats
I would like to tell the world about the load and popularity of my onion service. In particular, how many connection requests I've received, and how many of those I managed to reach the clients on, and how many rendezvous circuits I used on average when reaching rendezvous points, and so on.
One option is to put my statistics into my onion service descriptor -- then folks who want to record it over time can fetch it over time and record it as they like (e.g. by remembering the output of the HS_DESC_CONTENT event). (Even post proposal 224, they can do this, if they know my onion address name.)
I think this is in the "if somebody wrote it adequately, we'd take the patch" category.