I have developed several apps for Windows 8 and Windows Phone 8, and I am always amazed my one new feature that was introduced to the C# compiler: async and await.
If you are not familiar with the new async feature of C#, you could try to search for “C# async programming” on the Internet or go to this page on MSDN to read the documentation:
http://msdn.microsoft.com/en-us/library/vstudio/hh191443.aspx
If you have already used async/await for a while, you must be aware of the danger of async void (aka “fire-and-forget”), which could creates unobserved exception easily. In other words, you cannot simply use a try-catch block to catch the exception if you are awaiting an async void. There are already many blog posts and videos on this topic already, so I will not describe it again here. You can have a look at this video if you want to know more about the problem of async void: