In VersionedValue we introduced an unsafePeek method that requires the caller to have an higher level lock to guarantee safe access. One such example is acquiring the replication lock before calling unsafePeek in ReplCoordinatorImpl.

I believe having a `peek(lk)` method would be preferable than `unsafePeek()`. It is more standard in our codebase to use `WithLock` and it provides a level of safety (admittedly not perfect safety).