Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.ServiceModel/System/ServiceModel/Channels/StreamUpgradeInitiator.cs

@@ -0,0 +1,49 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+namespace System.ServiceModel.Channels
+{
+    using System.IO;
+    using System.Runtime;
+
+    public abstract class StreamUpgradeInitiator
+    {
+        protected StreamUpgradeInitiator()
+        {
+        }
+
+        public abstract string GetNextUpgrade();
+
+        public abstract Stream InitiateUpgrade(Stream stream);
+        public abstract IAsyncResult BeginInitiateUpgrade(Stream stream, AsyncCallback callback, object state);
+        public abstract Stream EndInitiateUpgrade(IAsyncResult result);
+
+        internal virtual IAsyncResult BeginOpen(TimeSpan timeout, AsyncCallback callback, object state)
+        {
+            return new CompletedAsyncResult(callback, state);
+        }
+
+        internal virtual void EndOpen(IAsyncResult result)
+        {
+            CompletedAsyncResult.End(result);
+        }
+
+        internal virtual IAsyncResult BeginClose(TimeSpan timeout, AsyncCallback callback, object state)
+        {
+            return new CompletedAsyncResult(callback, state);
+        }
+
+        internal virtual void EndClose(IAsyncResult result)
+        {
+            CompletedAsyncResult.End(result);
+        }
+
+        internal virtual void Open(TimeSpan timeout)
+        {
+        }
+
+        internal virtual void Close(TimeSpan timeout)
+        {
+        }
+    }
+}