1 files changed, 17 insertions, 0 deletions
diff --git a/src/mscorlib/src/System/Runtime/CompilerServices/AsyncStateMachineAttribute.cs b/src/mscorlib/src/System/Runtime/CompilerServices/AsyncStateMachineAttribute.cs
new file mode 100644
index 0000000000..d4402b311a
--- /dev/null
+++ b/src/mscorlib/src/System/Runtime/CompilerServices/AsyncStateMachineAttribute.cs
@@ -0,0 +1,17 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+
+using System;
+
+namespace System.Runtime.CompilerServices
+{
+    [Serializable, AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
+    public sealed class AsyncStateMachineAttribute : StateMachineAttribute
+    {
+        public AsyncStateMachineAttribute(Type stateMachineType)
+            : base(stateMachineType)
+        {
+        }
+    }
+}