iOS AVAudioSession 详解
iOS AVAudioSession 详解 - 简书
默认没有options，category 7种即可满足条件
- (BOOL)setCategory:(AVAudioSessionCategory)category error:(NSError **)outError API_AVAILABLE(ios(3.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);
有options，category 7种不满足条件，使用options组合操作
- (BOOL)setCategory:(AVAudioSessionCategory)category
withOptions:(AVAudioSessionCategoryOptions)options
error:(NSError **)outError