title: Integrate curio with pillow library
body: <p><strong>curio</strong> library provides async <code>aopen()</code> function, while <strong>pillow</strong> has it's own <code>Image.open</code>. I want to create thumbnail and suggest <strong>pillow</strong> is smart enough not to load all image into memory while creating thumbnail. It looks like this:</p>
  
  <pre><code>self.image = Image.open(path)
  self.image.thumbnail((300, 300))
  </code></pre>
  
  <p>How this can be integrated with the <strong>curio</strong> library?
  For me it looks like I have two options:</p>
  
  <ul>
  <li>Call <code>aopen()</code>, load data into memory, then create <code>Image</code> object from in-memory data and call <code>Image.thumbnail()</code> </li>
  <li>Make <code>Image.open()</code> async wrapping with <code>async_thread</code> decorator, but it requires fire all thread machinery.</li>
  </ul>
  
  <p>Is there some better approach for integrating curio and pillow for this task?</p>