This method allows you to call an arbitrary method as the next action in the action queue. This is useful if you want to execute code in after a specific action, i.e An actor arrives at a destination after traversing a path

const actor = new ex.Actor({...});

// move in a square at 200 pixels/second
// then trigger an alert when complete
     .moveTo(ex.vec(100, 0), 200)
     .moveTo(ex.vec(100, 100), 200)
     .moveTo(ex.vec(0, 100), 200)
     .moveTo(ex.vec(0, 0), 200)
     .callMethod(() => {