[xml] namespace structure and void * _private field

["David Hagood" <david hagood gmail com>]

Is the "void *    _private" member of the _xmlNs intended for the use of libXML2, or for the use of the program *using* libXML2.

In other words: If I wish to associate my own object with a given namespace, can I use the "_private" member of the namespace object, or do I need to do some other mechanism to map from a namespace into my object (
e.g. hashing on the URL of the namespace)?