code: protected void addToQueue(double closestDistanceSq , KdTree.Node node , P target ) {
  
  		if( !node.isLeaf() ) {
  			Helper h;
  			if( unused.isEmpty() ) {
  				h = new Helper();
  			} else {
  				h = unused.remove( unused.size()-1 );
  			}
  
  			h.closestPossibleSq = closestDistanceSq;
  			h.node = node;
  
  			queue.add(h);
  		} else {
  			checkBestDistance(node, target);
  		}
  	}
docs: Adds a node to the priority queue.
  
  @param closestDistanceSq The closest distance that a point in the region could possibly be target