如何用PHP实现异步请求、忽略返回值

/**
     * 发起异步请求，忽略返回值
     * @param $url  请求url
     * @return bool
     */
    function asyncPost($url)
    {
        $args = parse_url($url); //对url做下简单处理
        $host = $args['host']; //获取上报域名
        $path = $args['path'] . '?' . $args['query'];//获取上报地址
        $fp = fsockopen($host, 80, $error_code, $error_msg, 1);
        if (!$fp) {
            Log::record('获取错误信息:'.$error_code . ' _ ' . $error_msg, Log::INFO, true);
            Log::save('',LOG_PATH . '_' . date('y_m_d') . '.txt');
            return false;//
        } else {
            stream_set_blocking($fp, true);//开启了手册上说的非阻塞模式
            stream_set_timeout($fp, 1);//设置超时
            $header = "GET $path HTTP/1.1\r\n";  //注意 GET/POST请求都行 我们需要自己按照要求拼装Header http协议遵循1.1
            $header .= "Host: $host\r\n";
            $header .= "Connection: close\r\n\r\n";//长连接关闭
            fputs($fp, $header);
            fclose($fp);
        }
    }

$url[0] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
$url[1] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
$url[2] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
$url[3] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
$url[4] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
$url[5] = "http://XXXX/demo.php?a=1&b=2&c=3&d=4&e=5";
foreach($url as $k=>$val){
    asyncPost($val);
}