Why do bridges run the retry_dns callback?
In a4fcdc5dec, the following roles seem inconsistent:
+ CALLBACK(retry_dns, PERIODIC_EVENT_ROLE_ROUTER),
+ CALLBACK(check_dns_honesty, PERIODIC_EVENT_ROLE_RELAY),
It's probably unrelated, but I don't think clients write stats:
+ CALLBACK(write_stats_file, PERIODIC_EVENT_ROLE_ALL),
(Do onion services write stats?)
From https://trac.torproject.org/projects/tor/ticket/27080#comment:4