ContextBackends
constructor(log: EventLog, checkpoints: CheckpointStore, leases: LeaseStore, ledger: FailureLedger, snapshots: SnapshotTargets? = null, reservations: ReservationStore? = null, timers: TimerStore? = null, store: String = DEFAULT_STORE, groups: List<LogGroupBackends> = emptyList(), stores: PlacedStores = PlacedStores.NONE, snapshotTails: SnapshotTailReaders = SnapshotTailReaders.NONE)