public void Insert(int index, T item) { if (index > _size) throw new ArgumentOutOfRangeException(nameof(index)); if (_size == _items.Length) { EnsureCapacity(_size + 1); } if (index < _size) { Array.Copy(_items, index, _items, index + 1, _size - index); } _items[index] = item; _size++; _version++; }