PHP simulates multi-threaded requests

<?php
multi_threads_request($nodes){
$mh = curl_multi_init();
$curl_array = array();
foreach($nodes as $i => $url)
{
$curl_array[$i] = curl_init($url);
curl_setopt($curl_array[$i], CURLOPT_RETURNTRANSFER, true);
curl_multi_add_handle($mh, $curl_array[$i]);
}
$running = NULL;
do {
usleep(10000);
   curl_multi_exec($mh,$running);
} while($running > 0);
$res = array();
foreach($nodes as $i => $url)
{
$res[$url] = curl_multi_getcontent($curl_array[$i]);
}
foreach($nodes as $i => $url){
curl_multi_remove_handle($mh, $curl_array[$i]);
}
curl_multi_close($mh);
return $res;
}
print_r(multi_threads_request(array(
    &#39;http://www.163.com&#39;,
    &#39;http://www.baidu.com&#39;,
));