非同步程式設計概念

解說得很好
http://studyhost.blogspot.com/2012/06/metro-style-appnet-45.html

https://www.youtube.com/watch?v=8vcrjhaF1zE

https://hiskio.com/courses/182/lectures/7554


async 與 await

https://www.huanlintalk.com/2016/01/async-and-await.html

C# 非同步程式設計的 async void 與 async Task 的差異

https://csharpkh.blogspot.com/2017/10/c-async-void-async-task.html

https://codertw.com/%E4%BC%BA%E6%9C%8D%E5%99%A8/173292/