Provides classes that support interoperation between managed code and the Windows Runtime, and that enable the creation of Windows Runtime types with managed code. Commonly Used Types: System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeMarshal System.Runtime.InteropServices.WindowsRuntime.ReadOnlyArrayAttribute System.Runtime.InteropServices.WindowsRuntime.WriteOnlyArrayAttribute System.Runtime.InteropServices.WindowsRuntime.ReturnValueNameAttribute When using NuGet 3.x this package requires at least version 3.4.