求问，子进程里curl的问题？

$worker->onWorkerStart = function($worker) { 
    $url = 'https://www.baidu.com'; 
    $ch = curl_init($url); 
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
    $content = curl_exec($ch); 
    curl_close($ch); 
    echo $content; 
}