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

1. It fetches all data in memory which is often inefficient (see #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);
   }
   ```

1. `FetchMode::STANDARD_OBJECT` and `FetchMode::CUSTOM_OBJECT` are no longer supported.
2. `FetchMode::COLUMN` with a non-zero index is no longer supported.
3. Incompatible change in the `Connection::fetchColumn()` signature where the 3rd argument is now `$types`, not `$columnIndex`.

When the connection is lost or is closed, subsequent transaction will no longer be nested because they started in a brand new session. Our internal representation of the nesting shold take this into account

using params in query cache key generation.

Expressed PARAM_*_ARRAY through other constants to eliminate the dependency on the actual constant values

statements in a rewindable iterator. Skipped the test for iterating
multiple times with a message regarding that iterators are non
rewindable.