anchor.diff: +import 'dart:io';
   import 'dart:isolate';
  +import 'dart:convert';
   
   import 'package:logging/logging.dart';
   
   import 'package:dart_carte_du_jour/carte_de_jour.dart';
   
   class IsolateBuildPackageValidation {
  +  GoogleComputeEngineConfig _googleComputeEngineConfig;
  +
     ReceivePort isolateQueueServiceReceivePort = new ReceivePort();
   
     SendPort isolateQueueServiceSendPort;
  
positive.code: 
    void start() {
      isolateQueueServiceSendPort.send(isolateQueueServiceReceivePort.sendPort);
      _initListeners();
    }
  
    void stop() {
      // TODO: clean up lisenters and close ports.
    }
  
    void _initListeners() {
  
negative.code:       if (isCommand(QueueCommand.CHECK_PACKAGE, data)) {
          Package package = new Package.fromJson(data['message']);
          Package packageBuild = new Package(package.name, <Version>[], uploaders: []);
  
          // TODO: might be very wasteful to create a new PackageBuildInfoDataStore
          // on each CHECK_PACKAGE
          package.checkVersionBuilds(new PackageBuildInfoDataStore(_googleComputeEngineConfig))
          .listen((VersionBuild versionBuild) {
            Logger.root.finest("versionBuild = [${versionBuild.name}, ${versionBuild.version}, ${versionBuild.build}]");
            if (versionBuild.build) {
              packageBuild.versions.add(versionBuild.version);
            }
          }, onError: (error) {
            Logger.root.severe("QueueCommand.CHECK_PACKAGE stream error $error");
  