replacing a channel instead of calling `redirect()`

replace-channel.js

"use strict";

const { Cc, Ci, Cr } = require('chrome');

const ioservice = Cc['@mozilla.org/network/io-service;1'].getService(Ci.nsIIOService);
const events = require("sdk/system/events");

const listener = function(event) {
  let {subject, type, data} = event;

  if (type == 'http-on-modify-request') {
    let channel = subject.QueryInterface(Ci.nsIHttpChannel);
    let newUri = ioservice.newURI("http://foo.bar/baz", null, null);
    let newChan = ioservice.newChannelFromURI(newUri);

    newChan.loadInfo = channel.loadInfo

    newChan.loadGroup = channel.loadGroup
    newChan.notificationCallbacks = channel.notificationCallbacks;

    var loadCtx = newChan.notificationCallbacks.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsILoadContext);

    let loadGroup = channel.loadGroup;
    newChan.loadGroup = loadGroup;
    //loadGroup.addRequest(newChan, loadCtx)
    channel.loadGroup = null;


    newChan.loadFlags |= channel.loadFlags //| Ci.nsIChannel.LOAD_REPLACE;

    if (channel instanceof Ci.nsIHttpChannelInternal && newChan instanceof Ci.nsIHttpChannelInternal) {
      newChan.documentURI = channel.documentURI == channel.URI ? newChan.URI : channel.documentURI;
    }

    var eventSink = channel.notificationCallbacks.getInterface(Ci.nsIChannelEventSink);
    eventSink.asyncOnChannelRedirect(channel,newChan,Ci.nsIChannelEventSink.REDIRECT_INTERNAL,function() {});

    let replacementListener = {
      onDataAvailable: function() {},
      onStopRequest: function() {},
      onStartRequest: function() {}
    }

    channel.QueryInterface(Ci.nsITraceableChannel);
    let oldListener = channel.setNewListener(replacementListener);
    channel.notificationCallbacks = null;

    newChan.asyncOpen(oldListener,loadCtx)
    channel.cancel(Cr.NS_BINDING_REDIRECTED);
    loadGroup.removeRequest(channel, loadCtx, Cr.NS_BINDING_REDIRECTED)

  }
};


events.on('http-on-modify-request', listener);