anchor.diff:  // TODO(sigmund): deprecate this API when issue 2706 is fixed.
   Function expectAsyncUntil2(Function callback, Function isDone, {String id}) {
     return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke2;
  -}
  -
  -/**
  - * Wraps the [callback] in a new function and returns that function. The new
  - * function will be able to handle exceptions by directing them to the correct
  - * test. This is thus similar to expectAsync0. Use it to wrap any callbacks that
  - * might optionally be called but may never be called during the test.
  - * [callback] should take between 0 and 4 positional arguments (named arguments
  - * are not supported). [id] can be used to identify the callback in error
  - * messages (for example if it is called after the test case is complete).
  - */
  -Function _protectAsync(Function callback, {String id}) {
  -  return new _SpreadArgsHelper(callback, 0, -1, null, id).invoke;
   }
   
   /**
  
positive.code: 
  /**
   * Indicate that [callback] is expected to be called until [isDone] returns
   * true. The unittest framework checks [isDone] after each callback and only
   * when it returns true will it continue with the following test. Using
   * [expectAsyncUntil] will also ensure that errors that occur within
   * [callback] are tracked and reported. [callback] should take between 0 and
   * 4 positional arguments (named arguments are not supported). [id] can be
   * used to identify the callback in error messages (for example if it is called
   * after the test case is complete).
   */
  Function _expectAsyncUntil(Function callback, Function isDone, {String id}) {
    return new _SpreadArgsHelper(callback, 0, -1, isDone, id).invoke;
  }
  
  /**
   * Indicate that [callback] is expected to be called until [isDone] returns
   * true. The unittest framework check [isDone] after each callback and only
   * when it returns true will it continue with the following test. Using
   * [expectAsyncUntil0] will also ensure that errors that occur within
  
negative.code:     }
    }
  
    static String _makeCallbackId(String id, Function callback) {
      // Try to create a reasonable id.
      if (id != null) {
        return "$id ";
  