PHP开发中如何处理异步请求和并发处理

var xhr = new XMLHttpRequest();
xhr.open('GET', 'example.php', true);
xhr.onreadystatechange = function() {
   if (xhr.readyState === 4 && xhr.status === 200) {
     var response = xhr.responseText;
     // 处理返回的数据
   }
};
xhr.send();

$data = array('name' => 'John', 'age' => 30);
echo JSON_encode($data);

class WorkerThread extends Thread {
   private $data;
   public function __construct($data) {
      $this->data = $data;
   }
   public function run() {
      // 进行相应的处理
      // ...
      // 返回结果
      return $result;
   }
}

$threads = array();
$data = array('name' => 'John', 'age' => 30);
for ($i = 0; $i < 10; $i++) {
   $thread = new WorkerThread($data);
   $threads[] = $thread;
   $thread->start();
}
foreach ($threads as $thread) {
   $result = $thread->join();
   // 处理返回的结果
}

$processes = array();
for ($i = 0; $i < 10; $i++) {
   $pid = pcntl_fork();
   if ($pid == -1) {
      die('Fork failed');
   } elseif ($pid) {
      $processes[] = $pid;
   } else {
      // 进行相应的处理
      // ...
      exit();
   }
}
foreach ($processes as $pid) {
   pcntl_waitpid($pid, $status);
   // 处理返回的结果
}

use GuzzleHttpClient;
use GuzzleHttpPromise;

$client = new Client();
$promises = [];
for ($i = 0; $i < 10; $i++) {
   $promises[] = $client->getAsync('http://example.com');
}
$results = Promiseunwrap($promises);