title: How to set waits for object in pygame without freezing other objects
body: <p>Lets say I have class Truck. There are many instances of this class, on arrival to specific point instance should "unload" it's cargo - simply not move for N seconds, while other trucks should keep moving, unless they arrived to their unloading points.</p>
  
  <p>I do the stop part by setting movement vector to (0,0) and then resetting it back to original.</p>
  
  <p>But how to wait N seconds without freezing other cars? From what I've found so far I think I need to somehow apply <code>pygame.time.set_timer</code>, but it is really confusing for me.</p>