//typedef typename wf.Internal.GetAbiType<typename IEnumerator<T>.T_complex>.type T;
//BEGIN_INTERFACE_MAP(IteratorBase, ctl.WeakReferenceSource)
// INTERFACE_ENTRY(IteratorBase, IEnumerator<T>)
//END_INTERFACE_MAP(IteratorBase, ctl.WeakReferenceSource)
// UNO only
protected void CheckThread() => DispatcherQueue.CheckThreadAccess();