anchor.diff:      ArgResults options, {
       IncrementalKernelGenerator generator,
     }) async {
  -    final Uri _filenameUri = Uri.base.resolve(new Uri.file(filename).toString());
  +    _filename = filename;
       _kernelBinaryFilename = "$filename.dill";
       final String boundaryKey = new Uuid().generateV4();
       _outputStream.writeln("result $boundaryKey");
  
positive.code:   BinaryPrinterFactory printerFactory;
  
    IncrementalKernelGenerator _generator;
    String _kernelBinaryFilename;
  
    @override
  
negative.code:   }
  
    Uri _ensureFolderPath(String path) {
      // This is a URI, not a file path, so the forward slash is correct even
      // on Windows.
      if (!path.endsWith('/')) {
        path = '$path/';
      }
      return Uri.base.resolve(path);
    }
  
    /// Runs the given function [f] in a Zone that redirects all prints into
  