@Override
    public int encode(ByteBuffer buffer) {
        super.encodeThis(buffer);
        putString(fieldName, buffer);
        encodeFeatures(features, buffer);
        encodeFeatures(rangeFeatures, buffer);
        return 1;  // number of encoded stack dump items
    }
Returns a mutable collection of range feature entries.
container-search/src/main/java/com/yahoo/prelude/query/PredicateQueryItem.java