<PackageReference Include="System.Reactive" Version="6.0.0-preview.16" />

NamespaceDoc

class NamespaceDoc
The System.Reactive.PlatformServices namespace contains interfaces and classes used by the runtime infrastructure of Reactive Extensions. Those are not intended to be used directly from user code and are subject to change in future releases of the product.
using System.Runtime.CompilerServices; namespace System.Reactive.PlatformServices { [CompilerGenerated] internal class NamespaceDoc { } }