anchor.diff:        help: 'Includes sources into generated dill file. Having sources'
             ' allows to effectively use observatory to debug produced'
             ' application, produces better stack traces on exceptions.',
  -      defaultsTo: true);
  +      defaultsTo: true)
  +  ..addFlag('unsafe-package-serialization',
  +      help: 'Potentially unsafe: Does not allow for invalidating packages, '
  +          'additionally the output dill file might include more libraries than '
  +          'needed. The use case is test-runs, where invalidation is not really '
  +          'used, and where dill filesize does not matter, and the gain is '
  +          'improved speed.',
  +      defaultsTo: false,
  +      hide: true);
   
   String usage = '''
   Usage: server [options] [input.dart]
  
positive.code:             print: (Zone self, ZoneDelegate parent, Zone zone, String line) =>
                  _outputStream.writeln(line)));
    }
  }
  
  String _escapePath(String path) {
  
negative.code: /// Class that for test mocking purposes encapsulates creation of [BinaryPrinter].
  class BinaryPrinterFactory {
    /// Creates new [BinaryPrinter] to write to [targetSink].
    BinaryPrinter newBinaryPrinter(Sink<List<int>> targetSink) {
      return new LimitedBinaryPrinter(targetSink, (_) => true /* predicate */,
          false /* excludeUriToSource */);
    }
  