         }
     }
     
-    /** Subcribes for iOS specific notifications to perform some actions. */
+    /** Subcribes for iOS specific notifications to perform cache cleaning. */
     private func subscribeForNotifications() {
         #if os(iOS)
             

    
    /** In memory cache for NSData. */
    private let cache           = NSCache()

    /** The file manager to use for all file operations. */
    private let fileManager     = NSFileManager.defaultManager()
    
    /** The configuration for cache. */
    private let cacheConfiguration = DataCacheConfiguration()
    
    /** Obsevers object from NSNotificationCenter. */
    private var observers = [AnyObject]()
    
    init(name: String?) {
        cache.totalCostLimit = Int(cacheConfiguration.maxMemoryCacheSize);

        }
    }
    
    /** Removes expired files. In addition removes 1/4 of files if total size exceeds `maxDiskCacheSize`. */
    private func cleanupCache() {
        privateQueue.addOperationWithBlock {
            let expirationDate = NSDate(timeIntervalSinceNow: -self.cacheConfiguration.maxCacheAge)
