public void Initialize() { var model = Enumerable .Range(0, 10000) .Select(i => new ItemModel(uid: i.ToString(), displayName: "Item " + i)) .ToImmutableList(); _subject = new BehaviorSubject <ImmutableList <ItemModel> >(model); _subject.ApplyOnCollection(this, Items, factory: () => new ItemVm(), syncer: (m, vm) => vm.ReadModel(m), trackBy: m => m.Uid, onRemove: vm => vm.Dispose()); }