public function onGetUser(GetUserForTokenEvent $event)
    {
        $userProvider = $event->getUserProvider();

        if (!$userProvider instanceof OAuthUserProviderInterface) {
            return;
        }

        $token = $event->getToken();

        if ($user = $userProvider->loadUserByOAuthCredentials($token)) {
            $token->setUser($user);
        }
    }