使用 guzzle 测试并发时遇到的一个关于 PHP return 的问题

代码如下

require './vendor/autoload.php';

use GuzzleHttp\Client;
use GuzzleHttp\Promise;

$client = new Client(['base_uri' => '127.0.0.1/']);


// Initiate each request but do not block
$promises = [
    'test1' => $client->getAsync('test.php?id=1')
];
// Wait on all of the requests to complete.
$results = Promise\unwrap($promises);


// You can access each result using the key provided to the unwrap
// function.

die(var_dump($results['test1']->getBody()->getContents()));

test.php文件如下

$id = $_GET['id'];

class test{
    public function __construct($id)
    {
        $this->id = $id;
    }

    public function  handle()
    {
        //return $this->id;
        echo  $this->id;

    }
}

$result = new test($id);
$result ->handle();

疑问：为什么用return 就返回不了数据，又用了ajax请求测试了一遍同样用return前台没接收到数据，但经常用的框架中为什么ajax请求用return就能返回对应的数据到前台？