/**
     * Does an asynchronous POST request. (Cannot access output)
     *
     * @static
     * @throws Exception
     * @param string $url
     * @param array $params
     * @return void
     */
    public static function curl_post_async($url, $params)
    {
        $post_params = array();
        foreach($params as $key => &$val) {
            if(is_array($val)) $val = implode(',', $val);
            $post_params[] = $key . '=' . urlencode($val);
        }

        $post_string = implode('&', $post_params);
        $parts = parse_url($url);

        $fp = fsockopen('127.0.0.1',
            isset($parts['port']) ? $parts['port'] : 80,
            $errno, $errstr, 30);

        if($fp == 0) throw new Exception("Couldn't open a socket to " . $url . " (" . $errstr . ")");

        $out = "POST " . $parts['path'] . " HTTP/1.1\r\n";
        $out .= "Host: " . $parts['host'] . "\r\n";
        $out .= "Content-Type: application/x-www-form-urlencoded\r\n";
        $out .= "Content-Length: " . strlen($post_string) . "\r\n";
        $out .= "Connection: Close\r\n\r\n";
        if(isset($post_string)) $out .= $post_string;

        fwrite($fp, $out);
        fclose($fp);
    }