@Override
    public RankProperties clone() {
        Map<String, List<Object>> clone = new LinkedHashMap<>();
        for (Map.Entry<String, List<Object>> entry : properties.entrySet())
            clone.put(entry.getKey(), new ArrayList<>(entry.getValue()));
        return new RankProperties(clone);
    }
Encodes this in a binary internal representation and returns the number of property maps encoded (0 or 1)
container-search/src/main/java/com/yahoo/search/query/ranking/RankProperties.java