presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/ReorderJoins.java/MultiJoinNode/hashCode
class MultiJoinNode:        @Override
        public int hashCode()
        {
            return Objects.hash(sources, ImmutableSet.copyOf(extractConjuncts(filter)), outputSymbols, pushedProjectionThroughJoin);
        }