anchor.diff:     */
     static const String INCREMENTAL_RESOLUTION_VALIDATION =
         "incremental-resolution-validation";
  +
  +  /**
  +   * The name of the option used to cause instrumentation to also be written to
  +   * a local file.
  +   */
  +  static const String INSTRUMENTATION_LOG_FILE = "instrumentation-log-file";
   
     /**
      * The name of the option used to enable instrumentation.
  
positive.code:       defaultSdk = DirectoryBasedDartSdk.defaultSdk;
      }
  
      InstrumentationService service =
          new InstrumentationService(instrumentationServer);
      service.logVersion(
  
negative.code:    * Create and return the parser used to parse the command-line arguments.
     */
    CommandLineParser _createArgParser() {
      CommandLineParser parser =
          new CommandLineParser(alwaysIgnoreUnrecognized: true);
      parser.addOption(
          CLIENT_ID,
          help: "an identifier used to identify the client");
  