Internal implementation package not meant for direct consumption. Please do not reference directly. Provides types that support COM interop and platform invoke services. Commonly Used Types: System.Runtime.InteropServices.GCHandle System.Runtime.InteropServices.GuidAttribute System.Runtime.InteropServices.COMException System.DllNotFoundException System.Runtime.InteropServices.DllImportAttribute When using NuGet 3.x this package requires at least version 3.4.