anchor.diff:        ]);
       }
       return new _ServeOptions._(
  +        hostName: argResults[_hostname] as String,
           serveTargets: serveTargets,
           assumeTty: argResults[_assumeTty] as bool,
           deleteFilesByDefault: argResults[_deleteFilesByDefault] as bool);
  
positive.code: 
  const _assumeTty = 'assume-tty';
  const _deleteFilesByDefault = 'delete-conflicting-outputs';
  
  /// Unified command runner for all build_runner commands.
  class BuildCommandRunner extends CommandRunner {
  
negative.code: 
  /// Extends [_WatchCommand] with dev server functionality.
  class _ServeCommand extends _WatchCommand {
    _ServeCommand() {
      argParser
        ..addOption(_hostname,
            help: 'Specify the hostname to serve on', defaultsTo: 'localhost');
    }
  
    @override
    String get name => 'serve';
  
  