/**
* {@inheritDoc}
*/
public function compareState(SnapshotInterface $snapshot)
{
$state = $snapshot->getState();
if (!is_array($state)) {
throw new \UnexpectedValueException(__CLASS__ . ' can only handle array-serialized state');
}
$objectState = (array) $snapshot->getObject();
$snapshotState = $snapshot->getState();
if ($objectState === $snapshotState) {
return null;
}
return array_diff($objectState, $snapshotState);
}
