title: How can I download a file using window.fetch?
body: <p>If I want to download a file, what should I do in the <code>then</code> block below?</p>
  
  <pre><code>function downloadFile(token, fileId) {
    let url = `https://www.googleapis.com/drive/v2/files/${fileId}?alt=media`;
    return fetch(url, {
      method: 'GET',
      headers: {
        'Authorization': token
      }
    }).then(...);
  }
  </code></pre>
  
  <p>Note the codes are in client-side.</p>