firefox插件更改响应代码

Question

我有一个扩展程序正在检查http-on-examine-response侦听器中的响应。在监听器中，可以通过httpChannel更改标头，并通过nsITraceableChannel我们可以更改响应内容。

但是如何在http-on-examine-response监听器中更改响应代码（例如从407到200）？

一些代码：

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

Cu.import('resource://gre/modules/Services.jsm');

var observer = {
  observe: function(aSubject, aTopic, aData) {
    if (aTopic == 'http-on-examine-response') {
        console.log('we are in observer http-on-examine-response');
        var httpChannel = aSubject.QueryInterface(Ci.nsIHttpChannel);
        if(httpChannel.responseStatus == 407){
            httpChannel.responseStatus = 200; // <-- this is not working
        }
    }

  }
};

Services.obs.addObserver(observer, 'http-on-examine-response', false);


exports.onUnload = function (aData, aReason) {
  Services.obs.removeObserver(observer, 'http-on-examine-response');
};