iri based on value from persister

[wesol05]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	-
License	MIT
Doc PR	-

When using custom data persister, we don't pass id, but we want to somehow retrieve it. Unfortunately, returned object (with set id, is not taking under consideration when iri is set).

Example data persister:

public function persist($data)
    {
        $core = $this->transformer->toCore($data);

        $this->entityManager->persist($core);
        $this->entityManager->flush();

        return $this->transformer->toHttp($core);
    }

[dunglas]

Good catch! Can you just fix the test please?

[soyuka]

This change has a open discussion here: #2235 (comment) and I believe it breaks a feature (see WriteListenerTest::testOnKernelViewWithControllerResultAndPersistWithImmutableResource, the resource isn't immutable anymore?) ?

[flug]

@wesol05 Up is this pull request still valid?