This article serves as a supplement to Microsoft's C++/WinRT documentation. This article serves as a supplement to Microsoft's C++/WinRT documentation. Microsoft's docs provide a solid overview of asynchronous concepts and usage; however, they are ambiguous on several key points.Before diving into this article, you should first read Concurrency and asynchronous operations with C++/WinRT and Advanced concurrency and asynchrony with C++/WinRT. It's also helpful to have gone through my C++ coroutines tutorial (Chinese).