presto-main/src/main/java/io/prestosql/operator/NestedLoopBuildOperator.java/NestedLoopBuildOperatorFactory/createOperator
class NestedLoopBuildOperatorFactory:        @Override
        public Operator createOperator(DriverContext driverContext)
        {
            checkState(!closed, "Factory is already closed");
            OperatorContext operatorContext = driverContext.addOperatorContext(operatorId, planNodeId, NestedLoopBuildOperator.class.getSimpleName());
            return new NestedLoopBuildOperator(operatorContext, nestedLoopJoinBridgeManager.getJoinBridge(driverContext.getLifespan()));
        }