private void prepareRankFeaturesFromModel(Ranking ranking) {
        Item root = getQueryTree().getRoot();
        if (root != null) {
            List<Item> tagged = setUniqueIDs(root);
            addLabels(tagged, ranking);
            addConnectivityRankProperties(tagged, ranking);
            addSignificances(tagged, ranking);
            addDocumentFrequencies(tagged, ranking);
        }
    }
Prepares this for binary serialization. For internal use.
container-search/src/main/java/com/yahoo/search/query/Model.java