The replication coordinator has variables _inShutdown and _inTerminalShutdown and it's not obvious what the difference is. The former seems to be related to shutting down just the replication subsystem based on this comment whereas the latter has a comment that it's related to terminal shutdown, but it's not clear what terminal shutdown is.

We should see if it's possible to get rid of one of these variables if they're more or less equivalent. If the two truly serve different purposes, then we should document that clearly and make the variable names clearer.