title: Async servlet pdf download via Spring Controller on Azure
body: <p>I have an Spring MVC Controller which serves application/pdf via Async servlet, allowing me to flush output stream response header type "application/pdf" immediately while response body is waiting serverside for internal service to return byte[] of pdf. There is no chunking.</p>
  
  <p>My observation is running this outside of azure web app (using gradle bootRun or weblogic) I get Chrome showing pdf download in progress immediately proving header flush worked.
  When the same code runs under azure web app the download works but the Chrome isn't showing download in progress suggesting azure isn't flushing the response header.
  The situation is worse when using azure front door as  again it's not flushing and it's also limiting the response to 30s before giving 503.</p>
  
  <p>I'm stumped so any help extremely grateful, I can supply code if needed.</p>
  
  <p>Ant</p>