public function logout()
    {
        if (is_null($userId = $this->getUserId())) {
            return null;
        }

        return $this->leave(static::USER_PREFIX . $userId);
    }
public function logout()
    {
        if (is_null($userId = $this->getUserId())) {
            return null;
        }

        return $this->leave(static::USER_PREFIX . $userId);
    }
public function logout ( ) { if ( is_null ( $ userId = $ this -> getUserId ( ) ) ) { return null ; } return $ this -> leave ( static :: USER_PREFIX . $ userId ) ; }
Logout with current sender's fd.

@return mixed
Logout with current sender s fd .