<PackageReference Include="System.Reactive" Version="6.0.1-preview.1" />

System.Reactive.Joins.ActivePlan<T1, T2, T3, T4, T5, T6, T7, T8>

sealed class ActivePlan<T1, T2, T3, T4, T5, T6, T7, T8> : ActivePlan
namespace System.Reactive.Joins { }