presto-main/src/main/java/io/prestosql/sql/planner/PlanFragmenter.java/PlanFragmenter/Fragmenter
class PlanFragmenter:        public Fragmenter(Session session, Metadata metadata, TypeProvider types, StatsAndCosts statsAndCosts)
        {
            this.session = requireNonNull(session, "session is null");
            this.metadata = requireNonNull(metadata, "metadata is null");
            this.types = requireNonNull(types, "types is null");
            this.statsAndCosts = requireNonNull(statsAndCosts, "statsAndCosts is null");
        }