ISubject<T> public interface ISubject<T> : ISubject<T, T>, IObserver<T>, IObservable<T> Documentation Code using System.Runtime.CompilerServices; namespace System.Reactive.Subjects { [System.Runtime.CompilerServices.NullableContext(2)] public interface ISubject<T> : ISubject<T, T>, IObserver<T>, IObservable<T> { } }