if !needSort {
		for k := n.kids; k != nil; k = k.next {
			if k.walkReadyInOrder(openParent, tmp, f) {
				return true
			}
		}
		return false
	}

	// Uncommon case: sort the child nodes. We remove the kids from the parent,
	// then re-insert after sorting so we can reuse tmp for future sort calls.
	*tmp = (*tmp)[:0]
	for n.kids != nil {
		*tmp = append(*tmp, n.kids)