         }
     }
     
-    public var currentTime: NSTimeInterval! {
+    public var currentTime: NSTimeInterval {
         get {
             if let playerItem = self.playerItem {
                 return CMTimeGetSeconds(playerItem.currentTime())

        }
    }
    
    public var bufferSize: Double = 10.0
    public var playbackEdgeTriggered: Bool = true

    public var maximumDuration: NSTimeInterval! {
        get {
            if let playerItem = self.playerItem {
                return CMTimeGetSeconds(playerItem.duration)

    private var playerView: PlayerView!
    private var timeObserver: AnyObject!
    
    // MARK: - object lifecycle

    public convenience init() {
        self.init(nibName: nil, bundle: nil)
