From e005156a79b955310f04a799f703dd73c7cd8482 Mon Sep 17 00:00:00 2001
From: Maksym Koshovyi <maximkoshevoi61@gmail.com>
Date: Sat, 14 Aug 2021 15:53:13 +0300
Subject: [PATCH] Result of IChangeToken.RegisterChangeCallback is nullable

---
 .../ref/Microsoft.Extensions.Primitives.cs                      | 2 +-
 .../Microsoft.Extensions.Primitives/src/IChangeToken.cs         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.cs b/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.cs
index ed9ba055c5a4c..9cdfe02a6bf4d 100644
--- a/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.cs
+++ b/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.cs
@@ -36,7 +36,7 @@ public partial interface IChangeToken
     {
         bool ActiveChangeCallbacks { get; }
         bool HasChanged { get; }
-        System.IDisposable RegisterChangeCallback(System.Action<object?> callback, object? state);
+        System.IDisposable? RegisterChangeCallback(System.Action<object?> callback, object? state);
     }
     public readonly partial struct StringSegment : System.IEquatable<Microsoft.Extensions.Primitives.StringSegment>, System.IEquatable<string>
     {
diff --git a/src/libraries/Microsoft.Extensions.Primitives/src/IChangeToken.cs b/src/libraries/Microsoft.Extensions.Primitives/src/IChangeToken.cs
index f34122c21f723..650e89ab784c4 100644
--- a/src/libraries/Microsoft.Extensions.Primitives/src/IChangeToken.cs
+++ b/src/libraries/Microsoft.Extensions.Primitives/src/IChangeToken.cs
@@ -28,6 +28,6 @@ public interface IChangeToken
         /// <param name="callback">The <see cref="Action{Object}"/> to invoke.</param>
         /// <param name="state">State to be passed into the callback.</param>
         /// <returns>An <see cref="IDisposable"/> that is used to unregister the callback.</returns>
-        IDisposable RegisterChangeCallback(Action<object?> callback, object? state);
+        IDisposable? RegisterChangeCallback(Action<object?> callback, object? state);
     }
 }