presto-benchmark/src/main/java/io/prestosql/benchmark/AbstractSimpleOperatorBenchmark.java/AbstractSimpleOperatorBenchmark/createDriverFactory
class AbstractSimpleOperatorBenchmark:    protected DriverFactory createDriverFactory()
    {
        List<OperatorFactory> operatorFactories = new ArrayList<>(createOperatorFactories());

        operatorFactories.add(new NullOutputOperatorFactory(999, new PlanNodeId("test")));

        return new DriverFactory(0, true, true, operatorFactories, OptionalInt.empty(), UNGROUPED_EXECUTION);
    }