C# Language Pseudocode for async/await keywords


Example

Consider a simple asynchronous method:

async Task Foo()
{
    Bar();
    await Baz();
    Qux();
}

Simplifying, we can say that this code actually means the following:

Task Foo()
{
    Bar();
    Task t = Baz();
    var context = SynchronizationContext.Current;
    t.ContinueWith(task) =>
    {
        if (context == null)
            Qux();
        else
            context.Post((obj) => Qux(), null);
    }, TaskScheduler.Current);

    return t;
}

It means that async/await keywords use current synchronization context if it exists. I.e. you can write library code that would work correctly in UI, Web, and Console applications.

Source article.