public void addFeature(String key, String value, long subQueryBitmap) {
        addFeature(new Entry(key, value, subQueryBitmap));
    }
Adds a feature/value-pair to the predicate query.

@param key name of the feature to be set in this query
@param value value of the feature
@param subQueryBitmap bitmap specifying which sub queries this feature applies to
container-search/src/main/java/com/yahoo/prelude/query/PredicateQueryItem.java