presto-main/src/main/java/io/prestosql/operator/RowNumberOperator.java/RowNumberOperator/duplicate
class RowNumberOperator:        @Override
        public OperatorFactory duplicate()
        {
            return new RowNumberOperatorFactory(operatorId, planNodeId, sourceTypes, outputChannels, partitionChannels, partitionTypes, maxRowsPerPartition, hashChannel, expectedPositions, joinCompiler);
        }