Comment 1 for bug 1579057

For future reference, the catacomb stuff is a red herring -- that's pure infrastructure, and it's not surprising to see it because it's useful for most workers.

The actual problem was a leaked reference to an internal map that should have stayed inside uniter/remotestate.Watcher.Snapshot where it's safely mutexed.

Currently merging https://github.com/juju/juju/pull/5356