docs: public boolean isCollidingWith(Resource that, int count) {
          assert that!=null;
          for(Resource r=that; r!=null; r=r.parent)
              if(this.equals(r) && r.numConcurrentWrite<count)
                  return true;
          for(Resource r=this; r!=null; r=r.parent)
              if(that.equals(r) && r.numConcurrentWrite<count)
                  return true;
          return false;
      }