presto-main/src/main/java/io/prestosql/cost/PlanNodeStatsEstimate.java/PlanNodeStatsEstimate/Builder
class PlanNodeStatsEstimate:        private Builder(double outputRowCount, PMap<Symbol, SymbolStatsEstimate> symbolStatistics)
        {
            this.outputRowCount = outputRowCount;
            this.symbolStatistics = symbolStatistics;
        }