public Iterator<Hit> unorderedDeepIterator() {
        return new DeepHitIterator(unorderedIterator(), false);
    }
Returns an iterator that does depth-first traversal of leaf hits of this group, in a potentially unsorted order.
As opposed to {@link #deepIterator()}, this method has no side-effect.

@return A modifiable iterator.
container-search/src/main/java/com/yahoo/search/result/HitGroup.java