public function disconnect(Client $client, $message = 'Goodbye.')
    {
        $this->fire(self::CLIENT_DISCONNECT, $client, $message);

        $this->log('Client disconnected: <pop>'.$client.'</pop>', Logger::INFO);

        $client->disconnect();

        $i = array_search($client, $this->clients);
        unset($this->clients[$i]);
    }