PHPDaemon\Clients\ICMP\Connection::sendEcho PHP Метод

    public function sendEcho($cb, $data = 'phpdaemon')
    {
        ++$this->seq;
        if (mb_orig_strlen($data) % 2 !== 0) {
            $data .= "";
        }
        $packet = pack('ccnnn', 8, 0, 0, Daemon::$process->getPid(), $this->seq) . $data;
        $packet = substr_replace($packet, self::checksum($packet), 2, 2);
        $this->write($packet);
        $this->onResponse->push([$cb, microtime(true)]);
    }