private static IEnumerable<Recorded<System.Reactive.Notification<SynchronizedFilesCountViewModel>>> CreateExpectedFileNotifications( IFileNotification[][] fileNotifications, int offset) { return fileNotifications.Aggregate(new List<int>(), (list, files) => { list.Add(list.LastOrDefault() + files.Length); return list; }) .Select((f, i) => OnNext(Subscribed + i + offset, new SynchronizedFilesCountViewModel(0, f))); }