SyncStateObserver

Allows observing of SyncState. A value is always available immediately for new observers. Assumes that old SyncStates are not relevant anymore, so the available Flow has a limited buffer size and will drop the oldest values as there's no point in waiting for slow collectors. In case a slow collector is interested in receiving all values, it should add a buffer of its own.

Suspends the caller until all pending events are processed, and the client has finished processing all pending events.

If Sync is ongoing, suspends the caller until it reaches a terminal state.