curl 异步请求

public function test()
    {

        $body = file_get_contents('php://input');
        $header = array(
            'application/json; charset=utf-8'
        );
        $url = 'https://www.aiotagro.com';
        $curl = curl_init();//初始化curl
        curl_setopt($curl, CURLOPT_HTTPHEADER, $header);
        curl_setopt($curl, CURLOPT_HEADER, 0);//返回response头部信息
        curl_setopt($curl, CURLOPT_URL, $url);//抓取指定网页
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_POST, true);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $body);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, false);//控制直接输出或缓存数据
        curl_setopt($curl, CURLOPT_TIMEOUT, 1);
        curl_exec($curl);//可输出缓存数据 $response
        curl_close($curl);
    }

注意：curl请求 返回的URL数据必须是直接echo 输出到页面，不能return 返回，不然curl 输出的就是空白数据