presto-main/src/main/java/io/prestosql/operator/StreamingAggregationOperator.java/StreamingAggregationOperatorFactory/duplicate
class StreamingAggregationOperatorFactory:        @Override
        public OperatorFactory duplicate()
        {
            return new StreamingAggregationOperatorFactory(operatorId, planNodeId, sourceTypes, groupByTypes, groupByChannels, step, accumulatorFactories, joinCompiler);
        }