title: Parallel upload of files from a directory in Google Cloud Storage
body: <p>I'm trying to write a Python utility function which uploads files from a directory to a destination folder. Although, the documentation provides a snippet with <code>blob.upload_from_filename()</code> for a single file and then it jumps to <code>gsutil -m</code> solution for multiple files.</p>
  <p>So far, I have found only 2 suboptimal solutions:</p>
  <ol>
  <li>Simple iteration of the single file operation</li>
  <li>Use of <code>subprocess</code> and hardcode the <code>gsutil</code> command.</li>
  </ol>
  <p>Is there any elegant solution for this issue or should I use Python's <code>multiprocessing</code>?</p>