this loop is kind weird, uncommon to see `shift` being used like this. I would probably write it like this:

```js
function fireAppCallbacks(error, app) {
  requestQueue.forEach(function(cb) {
    cb(error, app);
  });
  requestQueue.length = 0;
}
```

but it's OK to keep it as is since we probably won't need to change this code anytime soon and it's already working as expected.