Requests invocation of a block when specified times are traversed during normal rendering.
- iOS 11.0+
- macOS 10.13+
- Mac Catalyst 13.0+
- tvOS 11.0+
- watchOS 6.0+
An array containing the times for which the observer requests notification.
The serial queue the block should be unqueued on. If you pass
NULL, the main queue is used. Passing a concurrent queue results in undefined behavior.
The block to be invoked when any of the specified times is crossed during normal rendering.
Always pair a call to this method with a call to
remove. Releasing the observer without calling
remove results in undefined behavior.