Scheduler is responsible for triggering the scheduled callbacks. You should not use NSTimer. Instead use this class. There are 2 different types of callbacks (selectors):
- update selector: the ‘update’ selector will be called every frame. You can customize the priority.
- custom selector: A custom selector will be called every frame, or with a custom interval of time The ‘custom selectors’ should be avoided when possible. It is faster, and consumes less memory to use the ‘update selector’.