<PackageReference Include="System.Reactive" Version="4.2.0" />

Plan<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult>

class Plan<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, TResult> : Plan<TResult>