public static void TryRaiseReseted <T>(this VectorChangedEventHandler <T> handler, IObservableVector <T> owner)
 => handler?.Invoke(owner, new VectorChangedEventArgs(CollectionChange.Reset, 0));
 public static void TryRaiseInserted(this VectorChangedEventHandler <object> handler, IObservableVector <object> owner, uint index)
 => handler?.Invoke(owner, new VectorChangedEventArgs(CollectionChange.ItemInserted, index));
 public static void TryRaiseRemoved <T>(this VectorChangedEventHandler <T> handler, IObservableVector <T> owner, uint index)
 => handler?.Invoke(owner, new VectorChangedEventArgs(CollectionChange.ItemRemoved, index));