Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/CompletedAsyncResult.cs

@@ -0,0 +1,69 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Runtime
+{
+    using System;
+    using System.Threading;
+
+    //An AsyncResult that completes as soon as it is instantiated.
+    class CompletedAsyncResult : AsyncResult
+    {
+        public CompletedAsyncResult(AsyncCallback callback, object state)
+            : base(callback, state)
+        {
+            Complete(true);
+        }
+
+        [Fx.Tag.GuaranteeNonBlocking]
+        public static void End(IAsyncResult result)
+        {
+            Fx.AssertAndThrowFatal(result.IsCompleted, "CompletedAsyncResult was not completed!");
+            AsyncResult.End<CompletedAsyncResult>(result);
+        }
+    }
+
+    class CompletedAsyncResult<T> : AsyncResult
+    {
+        T data;
+
+        public CompletedAsyncResult(T data, AsyncCallback callback, object state)
+            : base(callback, state)
+        {
+            this.data = data;
+            Complete(true);
+        }
+
+        [Fx.Tag.GuaranteeNonBlocking]
+        public static T End(IAsyncResult result)
+        {
+            Fx.AssertAndThrowFatal(result.IsCompleted, "CompletedAsyncResult<T> was not completed!");
+            CompletedAsyncResult<T> completedResult = AsyncResult.End<CompletedAsyncResult<T>>(result);
+            return completedResult.data;
+        }
+    }
+
+    class CompletedAsyncResult<TResult, TParameter> : AsyncResult
+    {
+        TResult resultData;
+        TParameter parameter;
+
+        public CompletedAsyncResult(TResult resultData, TParameter parameter, AsyncCallback callback, object state)
+            : base(callback, state)
+        {
+            this.resultData = resultData;
+            this.parameter = parameter;
+            Complete(true);
+        }
+
+        [Fx.Tag.GuaranteeNonBlocking]
+        public static TResult End(IAsyncResult result, out TParameter parameter)
+        {
+            Fx.AssertAndThrowFatal(result.IsCompleted, "CompletedAsyncResult<T> was not completed!");
+            CompletedAsyncResult<TResult, TParameter> completedResult = AsyncResult.End<CompletedAsyncResult<TResult, TParameter>>(result);
+            parameter = completedResult.parameter;
+            return completedResult.resultData;
+        }
+    }
+}