Imported Upstream version 4.0.1

Former-commit-id: 757121caeaad523350be5330f0a3ecc891c70fb8

external/referencesource/SMDiagnostics/System/ServiceModel/Diagnostics/Activity.cs

@@ -0,0 +1,52 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+
+namespace System.ServiceModel.Diagnostics
+{
+    using System.Runtime.Diagnostics;
+
+    class Activity : IDisposable
+    {
+        protected Guid parentId;
+        Guid currentId;
+        bool mustDispose = false;
+
+        protected Activity(Guid activityId, Guid parentId)
+        {
+            this.currentId = activityId;
+            this.parentId = parentId;
+            this.mustDispose = true;
+            DiagnosticTraceBase.ActivityId = this.currentId;
+        }
+
+        internal static Activity CreateActivity(Guid activityId)
+        {
+            Activity retval = null;
+            if (activityId != Guid.Empty)
+            {
+                Guid currentActivityId = DiagnosticTraceBase.ActivityId;
+                if (activityId != currentActivityId)
+                {
+                    retval = new Activity(activityId, currentActivityId);
+                }
+            }
+            return retval;
+        }
+
+        public virtual void Dispose()
+        {
+            if (this.mustDispose)
+            {
+                this.mustDispose = false;
+                DiagnosticTraceBase.ActivityId = this.parentId;
+            }
+            GC.SuppressFinalize(this);
+        }
+
+        protected Guid Id
+        {
+            get { return this.currentId; }
+        }
+    }
+}