         let maxX:Int = Int(floor(MKMapRectGetMaxX(rect) * scaleFactor))
         let minY:Int = Int(floor(MKMapRectGetMinY(rect) * scaleFactor))
         let maxY:Int = Int(floor(MKMapRectGetMaxY(rect) * scaleFactor))
-
+        
         var clusteredAnnotations = [MKAnnotation]()
-
+        
         lock.lock()
-
+        
         for i in minX...maxX {
-
+            
             for j in minY...maxY {
-
+                
                 let mapPoint = MKMapPoint(x: Double(i)/scaleFactor, y: Double(j)/scaleFactor)
                 
                 let mapSize = MKMapSize(width: 1.0/scaleFactor, height: 1.0/scaleFactor)

            toAdd.minusSet(toKeep as Set<NSObject>)
            let toRemove = NSMutableSet(set: before)
            toRemove.minusSet(after as Set<NSObject>)
        
            mapView.addAnnotations(toAdd.allObjects as! [MKAnnotation])
            mapView.removeAnnotations(toRemove.allObjects as! [MKAnnotation])
        }

        let zoomLevel:Int = FBClusteringManager.FBZoomScaleToZoomLevel(zoomScale)
        
        #if DEBUG
            println("FBCellSizeForZoomScale: \(zoomLevel)")
        #endif
        
        switch zoomLevel {
        case 12:
            return 96
