presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/ReorderJoins.java/JoinEnumerator/createJoinEnumerationResult
class JoinEnumerator:        private JoinEnumerationResult createJoinEnumerationResult(PlanNode planNode)
        {
            return JoinEnumerationResult.createJoinEnumerationResult(Optional.of(planNode), costProvider.getCost(planNode));
        }