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());
}