（）=>{}与async ()=>{}的区别

1·c# - Async lambda vs regular lambda in Task.Run - Stack Overflow

https://stackoverflow.com/questions/51111172/async-lambda-vs-regular-lambda-in-task-run

2·Async / Await Lambdas

https://stackoverflow.com/questions/25647062/async-await-lambdas

3·Is there a difference between lambdas declared with and without async

https://stackoverflow.com/questions/37133191/is-there-a-difference-between-lambdas-declared-with-and-without-async

 

三个来自外文的资料，还是很有用的