Inherits from YieldInstruction
Asynchronous operation coroutine.
异步操作协同程序。
You can yield until asynchronous operation continues, or manually check whether it's done (isDone) or progress (progress).
你可以yield直到异步操作继续,或手动检查它是完成的(isDone)或是进度中(progress)。
参见: Application.LoadLevelAsync, Application.LoadLevelAdditiveAsync, AssetBundle.LoadAsync.