title: PHP: Serve unfinished file for download
body: <p>I'm creating large file on demand. It can be video file from IP camera or zip or something else. For example:</p>
  
  <p><code>avconv -i http://CAM_IP:3000/T-8395-273-259 -c:v libx264 -movflags faststart -an output.mp4</code></p>
  
  <p>Is it possible to serve this file to download during this process using PHP?</p>