markSynced method
Marks the given queue entry as successfully synced.
Implementation
@override
Future<void> markSynced(String queueEntryId) async {
final i = _queue.indexWhere((e) => e.id == queueEntryId);
if (i < 0) throw StateError('Queue entry $queueEntryId not found');
_queue[i] = _queue[i].copyWith(synced: true);
}