Detecting something unique about current doctrine action

[pkly]

Hi, I was wondering about a following situation and just wanted to get a confirmation on it.

I know that work is done in a unit of work, but are those objects wholly unique?
I was wondering if the following logic is okay:

$entity = (new Entity())->setX(42);

$em->persist($entity);
$em->flush();

which then would in turn call a doctrine listener, which would do an action for the entity onPrePersist, like so

$otherEntity = (new OtherEntity())->setMyEntity($event->getObject());

$em->persist($otherEntity);
$em->flush();

Assuming I also I have another listener which is listening to let's say all doctrine events, if I look at the spl_object_ids of UnitOfWorks associated with events fired by doctrine at this point will I get one or two objects? I wrote an event linking library a while back for symfony but I wanted to appropriately link events which should fire after postFlush to the appropriate UnitOfWork.

Edit: It appears UOW is always the same, as it's created by the EM when that's initialized, so unless the manager itself would be reset it'd stay the same. Is there a good way to keep track of what is being changed through the events then?