The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 const { classes: Cc, interfaces: Ci } = Components;

 function handleRequest(request, response) {

   response.processAsync();

   let params = request.queryString.split("&");

   let index = params.filter((s) => s.contains("index="))[0].split("=")[1];

   let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);

   timer.initWithCallback(() => {

     // to avoid garbage collection

     timer = null;

     response.setStatusLine(request.httpVersion, index == 1 ? 101 : index * 100, "Meh");

     response.setHeader("Content-Type", "text/" + index, false);

     response.write(new Array(index * 10).join(index)); // + 0.01 KB

     response.finish();

   }, 10, Ci.nsITimer.TYPE_ONE_SHOT); // Make sure this request takes a few ms.

 }