Long-term implications of async/await for the programming model

[Karl]

@dabrahams

In all of the concurrency systems I know of, that means async code doing significant computation needs to be written with periodic cancellation checks—not so often as to slow things down, but often enough to be responsive. To me that seems like a pain to get right. Is there anything we can do to address that?

It should be possible to build tools which measure how long an async function continues executing after it was cancelled, or how many times it suspended despite being cancelled, etc. That would allow developers to find a balance between the cost of checking cancellation and having more unwanted tasks that continue to execute.