/// <summary>
/// Removes an element at the given index.
/// </summary>
/// <param name = "index">The index of the element to remove.</param>
public void RemoveAt(int index)
{
// Update pending operations to reflect the removed item.
_pendingOperations.RemoveInterval(new Interval <int>(index, index));
// Move all operations to the right of the removed index, one to the left.
int last = _list.Count - 1;
_pendingOperations.MoveInterval(new Interval <int>(index + 1, last), -1);
// Actual remove.
_list.RemoveAt(index);
}