Show HN: A Pattern for Async EventHandlers

I was just thinking about this the other day while looking through an MVVM framework that I was interested in using. I thought I'd see if there was an easy way to implement this.

I copied the TIL repository pattern from another Hacker News post and thought this would make a good write up. I'm interested in getting feedback from anybody about whether they think this would be a reasonable way to implement this pattern.