The methods has more limitations and caveats than provides real use:

1. It fetches all data in memory which is often inefficient (see doctrine#2718).
2. It fetches rows in memory one by one instead of using `fetchAll()`.
4. It doesn't allow to specify the statement fetch mode since it's instantiated internally.
5. It can be easily replaced with:
   ```php
   foreach ($conn->executeQuery($query, $params, $types) as $value) {
      yield $function($value);
   }
   ```