@Override
    public boolean equals(Object other) {
        if (other == this) return true;
        if ( ! (other instanceof RankProperties)) return false;

        return this.properties.equals(((RankProperties)other).properties);
    }
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