Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ServiceModel/System/ServiceModel/Diagnostics/TraceAsyncResult.cs

@@ -0,0 +1,58 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.ServiceModel.Diagnostics
+{
+    using System.Runtime;
+    using System.Diagnostics;
+
+    abstract class TraceAsyncResult : AsyncResult
+    {
+        static Action<AsyncCallback, IAsyncResult> waitResultCallback = new Action<AsyncCallback, IAsyncResult>(DoCallback);
+
+        protected TraceAsyncResult(AsyncCallback callback, object state) :
+            base(callback, state)
+        {
+            if (TraceUtility.MessageFlowTracingOnly)
+            {
+                this.CallbackActivity = ServiceModelActivity.CreateLightWeightAsyncActivity(Trace.CorrelationManager.ActivityId);
+                base.VirtualCallback = waitResultCallback;
+            } 
+            else if (DiagnosticUtility.ShouldUseActivity)
+            {
+                this.CallbackActivity = ServiceModelActivity.Current;
+                if (this.CallbackActivity != null)
+                {
+                    base.VirtualCallback = waitResultCallback;
+                }
+            }
+        }
+
+        public ServiceModelActivity CallbackActivity
+        {
+            get;
+            private set;
+        }
+
+        static void DoCallback(AsyncCallback callback, IAsyncResult result)
+        {
+            if (result is TraceAsyncResult)
+            {
+                TraceAsyncResult thisPtr = result as TraceAsyncResult;
+                Fx.Assert(thisPtr.CallbackActivity != null, "this shouldn't be hooked up if we don't have a CallbackActivity");
+
+                if (TraceUtility.MessageFlowTracingOnly)
+                {
+                    Trace.CorrelationManager.ActivityId = thisPtr.CallbackActivity.Id;
+                    thisPtr.CallbackActivity = null;
+                }
+
+                using (ServiceModelActivity.BoundOperation(thisPtr.CallbackActivity))
+                {
+                    callback(result);
+                }
+            }
+        }
+    }
+}