public Source <string, NotUsed> CurrentPersistenceIds() =>
 Source.ActorPublisher <string>(AllPersistenceIdsPublisher.Props(false, _writeJournalPluginId))
 .MapMaterializedValue(_ => NotUsed.Instance)
 .Named("CurrentPersistenceIds");
 public Source <string, NotUsed> PersistenceIds() =>
 // no polling for this query, the write journal will push all changes, i.e. no refreshInterval
 Source.ActorPublisher <string>(AllPersistenceIdsPublisher.Props(true, _writeJournalPluginId))
 .MapMaterializedValue(_ => NotUsed.Instance)
 .Named("PersistenceIds");