Results 3 issues of Oliver

``` _itemEndObserver = [[NSNotificationCenter defaultCenter] addObserverForName:AVPlayerItemDidPlayToEndTimeNotification object:self.playerItem queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification * _Nonnull note) { @strongify(self) if (!self) return; NSLog(@"%@",note.object); self.playState = ZFPlayerPlayStatePlayStopped; if (self.playerDidToEnd) self.playerDidToEnd(self); }]; ``` 这个通知的block会连续调用两次

I only want to use the simplest features to ensure a smooth experience

question