Read original post by Stephen Toub at Windows 8 App Developer Blog
In the blog post Diving Deep with Await and WinRT, we discussed the new async and await keywords in C# and Visual Basic and how you can use them to consume Windows Runtime (WinRT) asynchronous operations.
With some assistance from the .NET Base Class Libraries (BCL), you can also use these keywords to develop asynchronous operations that are then exposed via WinRT for other components built in other languages to consume. In this post, we’ll explore how to do so. (For overall details on implementing WinRT components with C# or Visual Basic, see Creating Windows Runtime Components in C# and Visual Basic.)