If concurrent updates strictly modify *different* members of the tasks
struct, the copying + lock-drop still constitutes a race condition:
The last updater always wins and sets tasks to its copy + changes.
This eliminates the other updater's changes.
1. Change config format to support multiple types
of snapshotting modes.
2. Implement a hacky way to support periodic or completely
manual snaphots.
In manual mode, the user has to trigger replication using the wakeup
mechanism after they took snapshots using their own tooling.
As indicated by the comment, a more general solution would be desirable,
but we want to get the release out and 'manual' mode is a feature that
some people requested...
Christian Schwarz