pocketmine\Server::broadcastMessage PHP Method

    public function broadcastMessage($message, $recipients = null)
    {
        if (!is_array($recipients)) {
            return $this->broadcast($message, self::BROADCAST_CHANNEL_USERS);
        }
        /** @var Player[] $recipients */
        foreach ($recipients as $recipient) {
            $recipient->sendMessage($message);
        }
        return count($recipients);
    }

 public function downloadFailCallback()
 {
     $this->isupdating = false;
     $this->server->broadcastMessage(new TranslationContainer("commands.upgrade.failed"));
 }