public void ActivityImportExport()
        {
            using (DiagnosticListener listener = new DiagnosticListener("TestingBasicIsEnabled"))
            {
                DiagnosticSource source = listener;
                var result = new List <KeyValuePair <string, object> >();

                bool seenPredicate = false;
                Func <string, object, object, bool> predicate = delegate(string name, object obj1, object obj2)
                {
                    seenPredicate = true;
                    return(true);
                };

                Activity importerActivity   = new Activity("activityImporter");
                object   importer           = "MyImporterObject";
                bool     seenActivityImport = false;
                Action <Activity, object> activityImport = delegate(Activity activity, object payload)
                {
                    Assert.Equal(activity.GetHashCode(), importerActivity.GetHashCode());
                    Assert.Equal(importer, payload);
                    seenActivityImport = true;
                };

                Activity exporterActivity   = new Activity("activityExporter");
                object   exporter           = "MyExporterObject";
                bool     seenActivityExport = false;
                Action <Activity, object> activityExport = delegate(Activity activity, object payload)
                {
                    Assert.Equal(activity.GetHashCode(), exporterActivity.GetHashCode());
                    Assert.Equal(exporter, payload);
                    seenActivityExport = true;
                };

                // Use the Subscribe that allows you to hook the OnActivityImport and OnActivityExport calls.
                using (listener.Subscribe(new ObserverToList <TelemData>(result), predicate, activityImport, activityExport))
                {
                    if (listener.IsEnabled("IntPayload"))
                    {
                        listener.Write("IntPayload", 5);
                    }

                    Assert.True(seenPredicate);
                    Assert.Equal(1, result.Count);
                    Assert.Equal("IntPayload", result[0].Key);
                    Assert.Equal(5, result[0].Value);

                    listener.OnActivityImport(importerActivity, importer);
                    Assert.True(seenActivityImport);

                    listener.OnActivityExport(exporterActivity, exporter);
                    Assert.True(seenActivityExport);
                }
            }
        }
        private void Handle(CommandStartedEvent @event)
        {
            var activity = new Activity(ActivityName);

            _diagnosticListener.OnActivityExport(activity, @event);

            if (_diagnosticListener.IsEnabled(ActivityStartEventName, @event))
            {
                _diagnosticListener.StartActivity(activity, @event);
            }
            else
            {
                activity.Start();
            }

            _activityMap.TryAdd(@event.RequestId, activity);
        }