Method maxDrivers

bolt/exec/tests/DriverTest.cpp:995–1000

      if (nullFunction()) {
        Operator::noMoreInput();
      }
    }

    Operator::noMoreInput();
  }

  RowVectorPtr getOutput() override {
    if (throwingMethod_ == ThrowNode::OperatorMethod::kGetOutput) {
      // Trigger a std::bad_function_call exception.