Async/Await

Using Async/Await from .NET 4.0
* Download from http://nuget.org/packages/Microsoft.CompilerServices.AsyncTargetingPack
* License is here http://www.microsoft.com/en-us/download/details.aspx?id=29576

Using TPL to implement APM
* http://blogs.msdn.com/b/pfxteam/archive/2011/06/27/using-tasks-to-implement-the-apm-pattern.aspx

Synchronization Contexts in UI, Console, ASP.NET etc
* http://msdn.microsoft.com/en-us/magazine/gg598924.aspx

When used on UI application, the code after "await" is executed by UI thread by default.  In Console application however, we need special treatments. See:
1. http://blogs.msdn.com/b/pfxteam/archive/2012/01/20/10259049.aspx
2. http://blogs.msdn.com/b/pfxteam/archive/2012/01/21/10259307.aspx
3. http://blogs.msdn.com/b/pfxteam/archive/2012/02/02/10263555.aspx