presto-main/src/main/java/io/prestosql/operator/ScanFilterAndProjectOperator.java/ScanFilterAndProjectOperator/createOperator
class ScanFilterAndProjectOperator:        @Override
        public SourceOperator createOperator(DriverContext driverContext)
        {
            checkState(!closed, "Factory is already closed");
            OperatorContext operatorContext = driverContext.addOperatorContext(operatorId, planNodeId, getOperatorType());
            return new WorkProcessorSourceOperatorAdapter(operatorContext, this);
        }