我的应用程序中有一个AVPlayer实例。我使用时间边界观察功能:[selfsetTimeObserver:[playeraddBoundaryTimeObserverForTimes:watchedTimesqueue:NULLusingBlock:^{NSLog(@"A:%i",[timeObserverretainCount]);[playerremoveTimeObserver:timeObserver];NSLog(@"B:%i",[timeObserverretainCount]);[selfsetTimeObserver:nil];}]];问题是，根据Instrument