Why folder id is null when I try to create folder?
<p>I use this code:</p>

<pre><code>$folder = new Google_Service_Drive_DriveFile([
  'name' =&gt; 'Invoices',
  'mimeType' =&gt; 'application/vnd.google-apps.folder'
]);

$req = $service-&gt;files-&gt;create($folder, [
  'fields' =&gt; 'id'
]);

var_dump($req-&gt;id); //NULL
</code></pre>

<p>Api version: v3.
Id is always null, but files uploading successfully.</p>