1 files changed, 27 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/Runtime/CompilerServices/IAsyncStateMachine.cs b/src/mscorlib/shared/System/Runtime/CompilerServices/IAsyncStateMachine.cs
new file mode 100644
index 0000000000..7fb7ea5395
--- /dev/null
+++ b/src/mscorlib/shared/System/Runtime/CompilerServices/IAsyncStateMachine.cs
@@ -0,0 +1,27 @@
+// 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.
+
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+//
+//
+// Represents state machines generated for asynchronous methods.
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Represents state machines generated for asynchronous methods.
+    /// This type is intended for compiler use only.
+    /// </summary>
+    public interface IAsyncStateMachine
+    {
+        /// <summary>Moves the state machine to its next state.</summary>
+        void MoveNext();
+        /// <summary>Configures the state machine with a heap-allocated replica.</summary>
+        /// <param name="stateMachine">The heap-allocated replica.</param>
+        void SetStateMachine(IAsyncStateMachine stateMachine);
+    }
+}