1 // Licensed to the .NET Foundation under one or more agreements.
2 // The .NET Foundation licenses this file to you under the MIT license.
3 // See the LICENSE file in the project root for more information.
4 
5 namespace System
6 {
7     public interface IObserver<in T>
8     {
OnNext(T value)9         void OnNext(T value);
OnError(Exception error)10         void OnError(Exception error);
OnCompleted()11         void OnCompleted();
12     }
13 }
14