gistfile1.swift

lazy var fetchedResultsController: NSFetchedResultsController<Event> = {
    let request: NSFetchRequest<Event> = Event.fetchRequest()
    request.fetchBatchSize = 20
    request.sortDescriptors = [NSSortDescriptor(key: "registered", ascending: false)]

    let controller = NSFetchedResultsController(fetchRequest: request, managedObjectContext:
    CoreDataStack.viewContext, sectionNameKeyPath: #keyPath(Event.sectionKey), cacheName: nil)

    controller.delegate = self
    try! controller.performFetch()

    return controller
}()