presto-main/src/main/java/io/prestosql/cost/CostCalculatorUsingExchanges.java/CostCalculatorUsingExchanges/visitValues
class CostCalculatorUsingExchanges:        @Override
        public PlanCostEstimate visitValues(ValuesNode node, Void context)
        {
            return costForSource(node, LocalCostEstimate.zero());
        }