title: GKRTree doesn't want to work at all, any other similar method?
body: <p>I'm making a game, where i need to define the object in the radius of the explosion in certain radius. Firstly, i was making it through distance between all objects, but i saw that there is GKRTree class in GameplayKit. But after many tries, it doesn't want to work at all. It just returns empty array in any case. I want to know, are GKRTree class broken or what. If yes, are there any other method to do the same stuff as GKRTree in swift or github. Because i dont want to calculate distance, since it can be use a lot of cpu. 
  Thanks</p>
  
  <p>Edit: I tried what is described in this answer <a href="https://stackoverflow.com/a/38655862/11687591">https://stackoverflow.com/a/38655862/11687591</a>, but it dont work. And there are no another solution about this problem. There is some links, where somebody is talking about broken gkrtree and there is no answer. <a href="https://www.reddit.com/r/swift/comments/63frk6/does_anyone_have_a_working_example_of_gkrtree/" rel="nofollow noreferrer">https://www.reddit.com/r/swift/comments/63frk6/does_anyone_have_a_working_example_of_gkrtree/</a>
  <a href="https://twitter.com/StayOnTheMove/status/1067067053419520000?s=20" rel="nofollow noreferrer">https://twitter.com/StayOnTheMove/status/1067067053419520000?s=20</a>
  And that's all. One things that i've tried that i created 2 circles. One of them is not moving and in one position all the time. Another is moving to my touch position. Second is smaller than the other one. Larger is a little bit transparent so i can see other circle. I also use print() to see all things that happening in the code. And after all of that, even if there is clearly situation where one circle is inside other one, gkrtree.entities method don't work and it returns empty array.</p>