private List<String> getChildren(String path, MemoryFileSystem.Node root) throws KeeperException.NoNodeException {
        validatePath(path);
        MemoryFileSystem.Node node = root.getNode(Paths.get(path), false);
        if (node == null) throw new KeeperException.NoNodeException(path);
        List<String> children = new ArrayList<>(node.children().keySet());
        if (! stableOrdering)
            Collections.shuffle(children);
        return children;
    }
sets the data of an existing node
zkfacade/src/main/java/com/yahoo/vespa/curator/mock/MockCuratorFramework.java