Calls the given function for each of the key/value pairs in the GTree.
The function is passed the key and value of each pair, and the given
data parameter. The tree is traversed in sorted order.
The tree may not be modified while iterating over it (you can't
add/remove items). To remove all items matching a predicate, you need
to add each item to a list in your GTraverseFunc as you walk over
the tree, then walk the list and remove each item.
Calls the given function for each of the key/value pairs in the GTree. The function is passed the key and value of each pair, and the given data parameter. The tree is traversed in sorted order. The tree may not be modified while iterating over it (you can't add/remove items). To remove all items matching a predicate, you need to add each item to a list in your GTraverseFunc as you walk over the tree, then walk the list and remove each item.