Compares two attributes based on the C14n specification.
- Namespace nodes have a lesser document order position than attribute nodes.
- An element's namespace nodes are sorted lexicographically by local name (the default namespace node, if one exists, has no local name and is therefore lexicographically least).
- An element's attribute nodes are sorted lexicographically with namespace URI as the primary key and local name as the secondary key (an empty namespace URI is lexicographically least).
@param obj0 casted Attr
@param obj1 casted Attr
@return returns a negative integer, zero, or a positive integer as obj0 is less than, equal to, or greater than obj1