Chunks de código de intento de PHP asíncrono o con threadings para obtener contenido de un site

ThreadingPHP

use GuzzleHttp\Client;



        $request = new AsyncWebRequest($this->_url,$url);
        if($request->start()) {
            while($request->isRunning()) {
                usleep(30);
            }
            if($request->join()) {
                if($request->httpCode === 200) {
                    $links = $this->processLinks($request->content,$url,$depth);

                    foreach($links as $link) {
                        //$this->crawlPage($link,$depth -1);
                        if(!$this->isValid($link,$depth)) {
                           continue;
                        }
                        $this->_seen[$link] = true;
                        $rq = new AsyncWebRequest($this->_url,$link);
                        if($rq->start()) {
                            while($rq->isRunning()) {
                                usleep(30);
                            }    
                            if($rq->join()) {
                                if($rq->httpCode === 200) {
                                    $ls = $this->processLinks($rq->content,$link,$depth);
                                    foreach($ls as $l) {
                                        if(!$this->isValid($l,$depth)) {
                                           continue;
                                        }
                                        $this->_seen[$l] = true;
                                    }
                                }
                            }
                        }
                        
                    }
                }
            }
        }
        
    class AsyncWebRequest extends Thread 
{
    public $baseUrl;
    public $uri;
    public $content = null;
    public $httpCode = null;

    public function __construct($baseUrl, $uri) 
    {
        $this->baseUrl = $baseUrl;
        $this->uri = $uri;
    }//__construct()

    public function run()
    {
        $client = new Client(array('base_uri' => $this->baseUrl));

        try {
            //$response = $client->request('GET', $this->uri, ['http_errors' => false]);
            $response = file_get_contents($this->uri);
//var_dump($response);exit();
            if($response) {
                $this->content = $response;    
                $this->httpCode = 200;
            } else {
                $this->httpCode = 404;
            }
            
        } catch (RequestException $e) {
            echo $e->getRequest();

            if ($e->hasResponse()) {
                echo $e->getResponse();
            }
        }
    }//run()
}//WorkerThreads