anchor.diff:  
   final Logger _logging = new Logger('sky_tools.run_mojo');
   
  +enum _MojoConfig { Debug, Release }
  +
   class RunMojoCommand extends Command {
     final name = 'run_mojo';
     final description = 'Run a Flutter app in mojo.';
     RunMojoCommand() {
       argParser.addFlag('android', negatable: false, help: 'Run on an Android device');
  +    argParser.addFlag('checked', negatable: false, help: 'Run Flutter in checked mode');
       argParser.addFlag('mojo-debug', negatable: false, help: 'Use Debug build of mojo');
       argParser.addFlag('mojo-release', negatable: false, help: 'Use Release build of mojo (default)');
   
  
positive.code:         args.add('--verbose');
        }
      }
      args.addAll(results.rest);
      return runCommandAndStreamOutput(command, args);
    }
  
    Future<int> _runLinux(ArgResults results, String appPath) async {
      String viewerPath = await _makePathAbsolute(await ArtifactStore.getPath(Artifact.SkyViewerMojo));
      String mojoBuildType = argResults['mojo-debug'] ? 'Debug' : 'Release';
      String mojoShellPath = await _makePathAbsolute(path.join(results['mojo-path'], 'out', mojoBuildType, 'mojo_shell'));
      List<String> args = [
        'file://${appPath}',
        '--url-mappings=mojo:sky_viewer=file://${viewerPath}'
      ];
      args.addAll(results.rest);
      return runCommandAndStreamOutput(mojoShellPath, args);
    }
  
  
negative.code:       _logging.severe('Cannot specify both --mojo-debug and --mojo-release');
        return 1;
      }
      List<String> args = [];
      if (argResults['checked']) {
        args.add('--args-for=mojo:sky_viewer --enable-checked-mode');
      }
      String mojoPath = argResults['mojo-path'];
      _MojoConfig mojoConfig = argResults['mojo-debug'] ? _MojoConfig.Debug : _MojoConfig.Release;
      String appPath = await _makePathAbsolute(argResults['app']);
  
      if (argResults['android']) {
        return _runAndroid(mojoPath, mojoConfig, appPath, args);
      } else {
        return _runLinux(mojoPath, mojoConfig, appPath, args);
      }
    }
  }
  