consider making RequestableInner implementable
currently that trait is sealed, which prevents implementing custom request. Right now i'm using arti with a (small) patch to send a query that's more lightweight than any other, just as a liveliness check. Sending anything more would be a waste of bandwidth and/or compute. I don't think RobotTxt
would be useful to anybody, so it shouldn't be merged into arti, but having a way to define it outside of arti itself would be nice.