presto-main/src/main/java/io/prestosql/operator/StatisticsWriterOperator.java/StatisticsWriterOperator/createOperator
class StatisticsWriterOperator:        @Override
        public Operator createOperator(DriverContext driverContext)
        {
            checkState(!closed, "Factory is already closed");
            OperatorContext context = driverContext.addOperatorContext(operatorId, planNodeId, StatisticsWriterOperator.class.getSimpleName());
            return new StatisticsWriterOperator(context, statisticsWriter, descriptor, rowCountEnabled);
        }