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