TokenCache class is passed to Facebook class to do `save()` and `load()` tokens. `TokenCache` has these functions:

```
public abstract void save(Bundle bundle);
public abstract Bundle load();

```

Now I want to do that saving and loading in multiple threads, so I run a `AsyncTask` in `load()`. The problem is it was already designed to return a Bundle! How to implement it so that the value only returned when the `AsyncTask` finishes?