trait Actor<T> {
  pub fn new(inner: T, pool: &Pool) -> Actor<T>;
  pub fn sync<U>(&self, msg: FnOnce(&mut T)) -> U;
  pub fn async<U>(&self, msg: FnOnce(&mut T)) -> Future<U>;
}

fn example() {
  // wake the main thread and create an actor on it
  let button = main_pool.sync(
    |pool| Actor::new(Button::new(), pool)
  );

  // an actor handle can be cloned, and the actors life cycle is tied
  // the existance of these handles. When a handle dies, the actor is released.
  let sent_button = button.clone();
  thread::spawn(move || {
    // the handle is Send even if the actor's inner body is not. Meaning it can live
    // on other thread and safely talk to the actor if they choose to.
    let old_color = sent_button.sync(|button| {
      // we can talk to the button on the main thread, a sync block blocks the current
      // thread until the message is reponded to. But has the advantage of being simpler
      // and avoiding allocation that is required by a Box<FnOnce>
      let old_color = button.color();
      button.set_color(Color.red);

      // data can be sent back if we choose to. This can help us fairy data too and from the actor
      old_color
    });

    // we can also async send to the actor, meaning it needn't block. These are handled
    // as soon as possible by the main thread, but may need to wait for other IO to complete.
    let some_future = sent_button.async(|button| {
      button.set_color(old_color);

      // it could be nice to self enqueue, since this is run in locked actor context
      // we can do a faster job of doing an async enqueue.
      after(|button| {

      });

      // also enqueue to the end of the queue, avoiding the fast path. Useful if you want
      // fair handling of actions.
      later(|button| {

      });

      // The API of those two are probably not possible, they will likely require a `Context` object
      // that will convay the types.
    });
  })

  // It's important to point out that the locking model means only one function is every being
  // applied to the object.
  button.async(|button| {

  });


}