public function send($command, $host = '')
    {
        $host = $host ?: $this->host;
        if (!$host) {
            throw new \InvalidArgumentException('Unknown host that will run the command');
        }
        $content = 'command='.urlencode($command);

        $fp = fsockopen($this->host, 80, $errno, $errstr, self::TIMEOUT);
        $request = 'POST '.$this->path." HTTP/1.1\r\n";
        $request .= 'Host: '.$host."\r\n";
        $request .= "Content-Type: application/x-www-form-urlencoded\r\n";
        $request .= 'Content-Length: '.strlen($content)."\r\n";
        $request .= "Connection: Close\r\n\r\n";
        $request .= $content;
        fwrite($fp, $request);
        fclose($fp);
    }