title: can curl_multi_add_handle() be called repeatly?
body: <pre><code>$queue = curl_multi_init();
  foreach ($urls as $url) {
          $ch = curl_init();
          curl_multi_add_handle($queue , $ch);
      }
  
  curl_multi_exec($queue, $active)
  ***then call curl_multi_add_handle() second time***
      foreach ($OtherUrls as $url) {
              $ch = curl_init();
              curl_multi_add_handle($queue , $ch);
          }
  </code></pre>
  
  <p>But found that $OtherUrls added are not been fetched. Seems curl_multi_add_handle() can not be called after curl_multi_exec() been called.</p>