title: How to send FormData with multiple files in chunks
body: <p>I need to send formData with multiple files to the server. Is it possible to send it in chunks and include "Transfer-Encoding: chunked"? Code that works is simple however it's sending the payload with Content-Length and not chunked.</p>
  
  <pre><code>const formData = new FormData()
  formData.append('textSample', textSample)
  formData.append('file1', somefile)
  formData.append('file2', somefile2)
  
  const xhr = new XMLHttpRequest()
  xhr.open('POST', "/upload")
  xhr.send(formData)
  </code></pre>
  
  <p>Is it even possible? Are there any libraries that support this? </p>