1 files changed, 17 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/AsyncCallback.cs b/src/mscorlib/shared/System/AsyncCallback.cs
new file mode 100644
index 0000000000..5c49535cff
--- /dev/null
+++ b/src/mscorlib/shared/System/AsyncCallback.cs
@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+/*============================================================
+**
+** Interface: AsyncCallbackDelegate
+**
+** Purpose: Type of callback for async operations
+**
+===========================================================*/
+
+namespace System
+{
+    [Serializable]
+    public delegate void AsyncCallback(IAsyncResult ar);
+}