internal void InitializeWorkItemMigrationContext()
        {
            var workItemServer = Engine.Source.GetService <WorkItemServer>();

            attachmentEnricher    = new TfsAttachmentEnricher(workItemServer, _config.AttachmentWorkingPath, _config.AttachmentMaxSize);
            workItemLinkEnricher  = Services.GetRequiredService <TfsWorkItemLinkEnricher>();
            embededImagesEnricher = Services.GetRequiredService <TfsEmbededImagesEnricher>();
            gitRepositoryEnricher = Services.GetRequiredService <TfsGitRepositoryEnricher>();
            nodeStructureEnricher = Services.GetRequiredService <TfsNodeStructure>();
            nodeStructureEnricher.Configure(new TfsNodeStructureOptions()
            {
                Enabled = true, NodeBasePaths = _config.NodeBasePaths, PrefixProjectToNodes = _config.PrefixProjectToNodes
            });
            nodeStructureEnricher.ProcessorExecutionBegin(null);

            _witClient = new WorkItemTrackingHttpClient(Engine.Target.Config.AsTeamProjectConfig().Collection, Engine.Target.Credentials);
            //Validation: make sure that the ReflectedWorkItemId field name specified in the config exists in the target process, preferably on each work item type.
            PopulateIgnoreList();
        }
        protected override void InternalExecute()
        {
            Log.LogInformation("WorkItemMigrationContext::InternalExecute ");
            if (_config == null)
            {
                throw new Exception("You must call Configure() first");
            }
            var workItemServer = Engine.Source.GetService <WorkItemServer>();

            attachmentEnricher    = new TfsAttachmentEnricher(workItemServer, _config.AttachmentWorkingPath, _config.AttachmentMaxSize);
            workItemLinkEnricher  = Services.GetRequiredService <TfsWorkItemLinkEnricher>();
            embededImagesEnricher = Services.GetRequiredService <TfsEmbededImagesEnricher>();
            gitRepositoryEnricher = Services.GetRequiredService <TfsGitRepositoryEnricher>();
            nodeStructureEnricher = Services.GetRequiredService <TfsNodeStructureEnricher>();
            _witClient            = new WorkItemTrackingHttpClient(Engine.Target.Config.AsTeamProjectConfig().Collection, Engine.Target.Credentials);
            //Validation: make sure that the ReflectedWorkItemId field name specified in the config exists in the target process, preferably on each work item type.
            PopulateIgnoreList();

            Log.LogInformation("Migrating all Nodes before the work item run.");
            nodeStructureEnricher.MigrateAllNodeStructures(_config.PrefixProjectToNodes, _config.NodeBasePaths);

            var stopwatch = Stopwatch.StartNew();
            //////////////////////////////////////////////////
            string sourceQuery =
                string.Format(
                    @"SELECT [System.Id], [System.Tags] FROM WorkItems WHERE [System.TeamProject] = @TeamProject {0} ORDER BY {1}",
                    _config.WIQLQueryBit, _config.WIQLOrderBit);

            // Inform the user that he maybe has to be patient now
            contextLog.Information("Querying items to be migrated: {SourceQuery} ...", sourceQuery);
            var sourceWorkItems = Engine.Source.WorkItems.GetWorkItems(sourceQuery);

            contextLog.Information("Replay all revisions of {sourceWorkItemsCount} work items?", sourceWorkItems.Count);
            //////////////////////////////////////////////////
            contextLog.Information("Found target project as {@destProject}", Engine.Target.WorkItems.Project.Name);
            //////////////////////////////////////////////////////////FilterCompletedByQuery
            if (_config.FilterWorkItemsThatAlreadyExistInTarget)
            {
                contextLog.Information("[FilterWorkItemsThatAlreadyExistInTarget] is enabled. Searching for work items that have already been migrated to the target...", sourceWorkItems.Count());
                sourceWorkItems = ((TfsWorkItemMigrationClient)Engine.Target.WorkItems).FilterExistingWorkItems(sourceWorkItems, new TfsWiqlDefinition()
                {
                    OrderBit = _config.WIQLOrderBit, QueryBit = _config.WIQLQueryBit
                }, (TfsWorkItemMigrationClient)Engine.Source.WorkItems);
                contextLog.Information("!! After removing all found work items there are {SourceWorkItemCount} remaining to be migrated.", sourceWorkItems.Count());
            }
            //////////////////////////////////////////////////

            var result = validateConfig.ValidatingRequiredField(Engine.Target.Config.AsTeamProjectConfig().ReflectedWorkItemIDFieldName, sourceWorkItems);

            if (!result)
            {
                var ex = new InvalidFieldValueException("Not all work items in scope contain a valid ReflectedWorkItemId Field!");
                Log.LogError(ex, "Not all work items in scope contain a valid ReflectedWorkItemId Field!");
                throw ex;
            }
            //////////////////////////////////////////////////
            _current       = 1;
            _count         = sourceWorkItems.Count;
            _elapsedms     = 0;
            _totalWorkItem = sourceWorkItems.Count;
            foreach (MigrationTools._EngineV1.DataContracts.WorkItemData sourceWorkItemData in sourceWorkItems)
            {
                var sourceWorkItem = TfsExtensions.ToWorkItem(sourceWorkItemData);
                workItemLog = contextLog.ForContext("SourceWorkItemId", sourceWorkItem.Id);
                using (LogContext.PushProperty("sourceWorkItemTypeName", sourceWorkItem.Type.Name))
                    using (LogContext.PushProperty("currentWorkItem", _current))
                        using (LogContext.PushProperty("totalWorkItems", _totalWorkItem))
                            using (LogContext.PushProperty("sourceWorkItemId", sourceWorkItem.Id))
                                using (LogContext.PushProperty("sourceRevisionInt", sourceWorkItem.Revision))
                                    using (LogContext.PushProperty("targetWorkItemId", null))
                                    {
                                        ProcessWorkItem(sourceWorkItemData, _config.WorkItemCreateRetryLimit);
                                        if (_config.PauseAfterEachWorkItem)
                                        {
                                            Console.WriteLine("Do you want to continue? (y/n)");
                                            if (Console.ReadKey().Key != ConsoleKey.Y)
                                            {
                                                workItemLog.Warning("USER ABORTED");
                                                break;
                                            }
                                        }
                                    }
            }
            //////////////////////////////////////////////////
            stopwatch.Stop();

            contextLog.Information("DONE in {Elapsed}", stopwatch.Elapsed.ToString("c"));
        }