async/await is not based on generators. It's a compile-time transform that hoists parts of your function into independently scheduled asynchronous tasks & task

async/await is not based on generators. It's a compile-time transform that hoists parts of your function into independently scheduled asynchronous tasks & task callbacks. So it's essentially automatic CPS + promises. That's why functions are tagged as 'async' or not-async in C#; if they are 'async' they produce a promise instead of a value. On a related note, part of C#'s async/await infrastructure is a scheduling system so that callbacks can be configured to run on a specific thread - i.e. you can kick off async work on the UI thread and the callbacks will run there, instead of on the threadpool thread that completed the work.