/// <summary>
/// Compares two nodes to determine their relative XML document order.
/// </summary>
/// <param name="x">The first node to compare.</param>
/// <param name="y">The second node to compare.</param>
/// <returns>
/// 0 if the nodes are equal;
/// -1 if x is before y;
/// 1 if x is after y.
/// </returns>
/// <exception cref="InvalidOperationException">
/// Thrown if the two nodes do not share a common ancestor.
/// </exception>
public int Compare(XNode?x, XNode?y)
{
return(XNode.CompareDocumentOrder(x, y));
}