diff --git a/src/Orleans.Streaming/Core/IAsyncBatchObserver.cs b/src/Orleans.Streaming/Core/IAsyncBatchObserver.cs
index 0a97e78101..c4dd4e40c7 100644
--- a/src/Orleans.Streaming/Core/IAsyncBatchObserver.cs
+++ b/src/Orleans.Streaming/Core/IAsyncBatchObserver.cs
@@ -74,7 +74,7 @@ public interface IAsyncBatchObserver<T>
         /// </para>
         /// </summary>
         /// <returns>A Task that is completed when the stream-complete operation has been accepted.</returns>
-        Task OnCompletedAsync();
+        Task OnCompletedAsync() => Task.CompletedTask;
 
         /// <summary>
         /// Notifies the consumer that the stream had an error.
diff --git a/src/Orleans.Streaming/Core/IAsyncObserver.cs b/src/Orleans.Streaming/Core/IAsyncObserver.cs
index b487ddcc1d..795bf9bf3f 100644
--- a/src/Orleans.Streaming/Core/IAsyncObserver.cs
+++ b/src/Orleans.Streaming/Core/IAsyncObserver.cs
@@ -46,7 +46,7 @@ public interface IAsyncObserver<in T>
         /// </para>
         /// </summary>
         /// <returns>A Task that is completed when the stream-complete operation has been accepted.</returns>
-        Task OnCompletedAsync();
+        Task OnCompletedAsync() => Task.CompletedTask;
 
         /// <summary>
         /// Notifies the consumer that the stream had an error.