默认情况下，CABasicAnimation是否在主线程或后台线程中运行
这比编码更像一个概念查询.我有一个自定义活动指示器，一个自定义视图.用户将拥有的唯一公共API是init(onFrame frame: CGRect)，startAnimating()和stopAnimating().
This is more a conceptual query than coding. I have a custom activity indicator, a custom view. The only public API, the user will have is the init(onFrame frame: CGRect), startAnimating() and stopAnimating().
所以，我想在startAnimating方法中知道是否应该创建一个线程(无论是main还是DispatchQoS)来运行动画.
So, I want to know in the startAnimating method, should I create a thread whether main or DispatchQoS to run the animation.
此外，如果我不将动画代码放入线程中，它将自动在主线程上运行吗?
Also, if I don't put the animation code in a thread, will it be automatically running on main thread?
与UIView的所有通信都必须在主线程上.所有Core Animation都会在后台线程上自动执行.因此，请不要与CABasicAnimation关联任何显式的多线程.
All communication with a UIView must be on the main thread. All Core Animation is automatically performed on a background thread. So do not do any explicit multithreading in connection with CABasicAnimation.