@Override
    public Predicate process(Predicate predicate, PredicateOptions options) {
        if (useConjunctionAlgorithm) {
            return transform(predicate);
        }
        return predicate;
    }
Transforms Conjunctions with only (negated) {@link FeatureSet} instances to {@link FeatureConjunction}.
The {@link FeatureConjunction}s are indexed by the {@link ConjunctionIndex}.

@author bjorncs
predicate-search/src/main/java/com/yahoo/search/predicate/optimization/FeatureConjunctionTransformer.java