faults property
What the client could not do with something the server sent.
The connection is still up and the peers still understand each other; one piece of data could not be taken in. Nothing is retried, so an app that cares has to decide for itself whether to re-sync or to tell the user.
Broadcast, and nothing is replayed: a fault reported before you subscribe is gone.
Implementation
Stream<SyncFault> get faults => _faults.stream;