System.Reactive.ObservableBase<T> public abstract class ObservableBase<T> : IObservable<T> Abstract base class for implementations of the IObservable<T> interface. Documentation Code namespace System.Reactive { public abstract class ObservableBase<[System.Runtime.CompilerServices.Nullable(2)] T> : IObservable<T> { public IDisposable Subscribe(IObserver<T> observer); protected abstract IDisposable SubscribeCore(IObserver<T> observer); protected ObservableBase(); } }