//public T? PeekAt(Index index) private protected virtual T PeekAtCore(int index) => _logic.PeekAt(index);
private protected sealed override T PeekAtCore(int index) => _logic.PeekAt(index).Unwrap(true);
//public T? PeekAt(Index index) private protected virtual T PeekAtCore(int index) => _logic.PeekAt(index);
private protected sealed override T PeekAtCore(int index) => _logic.PeekAt(index).Unwrap(true);