Thread returning to thread pool when using await

Question

However, with ASP.NET Web Api, if your request is coming in on one thread, and you await some function and call ConfigureAwait(false)

Answer 1

What's am I missing here?

You are missing compiler warnings

Warning CS1998 This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

Answer 2

The method foo isn't really asynchronous as there are no await calls in it.
Try adding await Task.Delay in there.