     return (maybeImage?.0, .Mishit)
   }
   
-  let prefetchQueue = NSOperationQueue()
-
-  private func prefetchQueueInit(){
-    prefetchQueue.maxConcurrentOperationCount = config.prefetchOprationCount
-    prefetchQueue.qualityOfService = NSQualityOfService.Background
-  }
-
-  public func prefetch(urls: [NSURL]) {
-    for url in urls {
-      prefetch(url)
-    }
-  }
-  
-  public func prefetch(url: NSURL) {
-    var op = NSOperation()
-    op.completionBlock = {
-      [weak self] in
-      self?.downloadToDisk(url)
-    }
-    prefetchQueue.addOperation(op)
-  }
-  
   private func downloadToDisk(url: NSURL) {
     let path = PIImageCache.filePath(url, config: config)
     if path == nil { return }

      }
    }
    return nil
  }
  
  internal enum Result {
    case Mishit, MemoryHit, DiskHit
  }
  
  internal func perform(url: NSURL) -> (UIImage?, Result) {


public class PIImageCache {
  
  //initialize
  
  private func myInit() {
    folderCreate()
    prefetchQueueInit()
