anchor.diff:              response.headers.set(HttpHeaders.CONTENT_LENGTH, end - start);
     
               // Set 'Partial Content' status code.
  -            response.statusCode = 206;
  +            response.statusCode = HttpStatus.PARTIAL_CONTENT;
               response.headers.set(HttpHeaders.CONTENT_RANGE,
                                    "bytes $start-${end - 1}/$length");
     
  
positive.code:       // If If-Modified-Since is present and file haven't changed, return 304.
        if (request.headers.ifModifiedSince != null &&
            !lastModified.isAfter(request.headers.ifModifiedSince)) {
          response.statusCode = 304;
          response.close();
          return;
        }
  
negative.code:   
                            default:
                              // File not found, fall back to 404.
                              request.response.statusCode = HttpStatus.NOT_FOUND;
                              request.response.write("File not found");
                              request.response.close();
                              break;
  