protected function userFromRecaller($recaller)
    {
        if (! $recaller->valid() || $this->recallAttempted) {
            return;
        }

        // If the user is null, but we decrypt a "recaller" cookie we can attempt to
        // pull the user data on that cookie which serves as a remember cookie on
        // the application. Once we have a user we can return it to the caller.
        $this->recallAttempted = true;

        $this->viaRemember = ! is_null($user = $this->provider->retrieveByToken(
            $recaller->id(), $recaller->token()
        ));

        return $user;
    }