This package enables Visual Studio 2012 projects targeting .NET Framework 4 (with KB2468871), Silverlight 4 and 5, and Windows Phone 7.5 (including any portable library combinations) to use the new 'async' and 'await' keywords. This package also includes Task-based extension methods that allow using some of the existing asynchronous APIs with the new language keywords. Windows Phone 8 projects can use this package to get access to async extension methods for the networking types.
This package is not supported in Visual Studio 2010, and is only required for projects targeting .NET Framework 4.5 or .NET for Windows Store apps when consuming a library that uses this package. For known issues, please see: http://blogs.msdn.com/b/bclteam/p/asynctargetingpackkb.aspx.
To install Async for .NET Framework 4, Silverlight 4 and 5, and Windows Phone 7.5 and 8, run the following command in the Package Manager Console