IsEmpty check in storage should not trigger reading from the mapper

[kachar]

$auth = $sm->get('zfcuser_auth_service');

if ($auth->hasIdentity()) {       // Mapper is called here
    $user = $auth->getIdentity(); // instead of here
    // ...
}

// Zend\Authentication\AuthenticationService

public function hasIdentity()
{
    return !$this->getStorage()->isEmpty();  // Mapper reads the data inside the isEmpty check
}

public function getIdentity()
{
    $storage = $this->getStorage();

    if ($storage->isEmpty()) {
        return null;
    }

    return $storage->read(); // Here we are using already cached data
}

What do you think about this proposal?