Replace setImmediate with setTimeout 0 (#14)

Author: ericwooley

lib/XMLHttpRequest.js

@@ -636,14 +636,14 @@ function XMLHttpRequest(opts) {
   this.dispatchEvent = function (event) {
     if (typeof self["on" + event] === "function") {
       if (this.readyState === this.DONE && settings.async)
-        setImmediate(function() { self["on" + event]() })
+        setTimeout(function() { self["on" + event]() }, 0)
       else
         self["on" + event]()
     }
     if (event in listeners) {
       for (let i = 0, len = listeners[event].length; i < len; i++) {
         if (this.readyState === this.DONE)
-          setImmediate(function() { listeners[event][i].call(self) })
+          setTimeout(function() { listeners[event][i].call(self) }, 0)
         else
           listeners[event][i].call(self)
       }