presto-main/src/main/java/io/prestosql/operator/OrderByOperator.java/OrderByOperator/createOperator
class OrderByOperator:        @Override
        public Operator createOperator(DriverContext driverContext)
        {
            checkState(!closed, "Factory is already closed");

            OperatorContext operatorContext = driverContext.addOperatorContext(operatorId, planNodeId, OrderByOperator.class.getSimpleName());
            return new OrderByOperator(
                    operatorContext,
                    sourceTypes,
                    outputChannels,
                    expectedPositions,
                    sortChannels,
                    sortOrder,
                    pagesIndexFactory,
                    spillEnabled,
                    spillerFactory,
                    orderingCompiler);
        }