default Path childPath() {
		final Iterator<T> it = pathFromAncestorIterator(root());
		final int[] path = new int[level()];

		T tree = null;
		int index = 0;
		while (it.hasNext()) {
			final T child = it.next();
			if (tree != null) {
				path[index++] = tree.indexOf(child);
			}

			tree = child;
		}

		assert index == path.length;

		return new Path(path);
	}
Return the path of {@code this} child node from the root node. You will
get {@code this} node, if you call {@link #childAtPath(Path)} on the
root node of {@code this} node.
{@snippet lang="java":
final Tree<?, ?> node = null; // @replace substring='null' replacement="..."
final Tree<?, ?> root = node.getRoot();
final int[] path = node.childPath();
assert node == root.childAtPath(path);
}

@since 4.4

@see #childAtPath(Path)

@return the path of {@code this} child node from the root node.
jenetics.ext/src/main/java/io/jenetics/ext/util/Tree.java