@property (nonatomic, strong, readonly) UIView *brightnessView;

/// 0..1
@property (nonatomic, assign, readwrite) float volume;
@property (nonatomic, copy, readwrite, nullable) void(^volumeChanged)(float volume);

/// 0.1..1
@property (nonatomic, assign, readwrite) float brightness;
@property (nonatomic, copy, readwrite, nullable) void(^brightnessChanged)(float brightness);