title: How to set dynamic filename?
body: <p>Using retrofit 2, how would I set a dynamic name for the uploaded file?</p>
  
  <p>Currently, it's like this:</p>
  
  <pre><code>@Part("avatar\"; filename=\"image\" ") RequestBody image,
  </code></pre>
  
  <p>However, the uploaded file name would be <code>image</code> without the extension.
  Any recommendation on this case?</p>