public static List<String> serialize(InnerNode node) {
        List<String> ret = new ArrayList<>();
        for (Map.Entry<String, LeafNode<?>> entry : getAllDescendantLeafNodes(node).entrySet()) {
            ret.add(entry.getKey() + " " + entry.getValue().toString());
        }
        return ret;
    }
Returns the serialized representation of the given node.
<p>
Declared static, instead of InnerNode member, to avoid a public 0-arg method with a commonly used name.

@param node The inner node
@return a list of strings, containing the serialized representation of this config
config-lib/src/main/java/com/yahoo/config/ConfigInstance.java