anchor.diff:  // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
   
  -import 'dart:math';
  +import 'dart:math' as math;
   
   import 'package:flutter/gestures.dart';
   import 'package:flutter/rendering.dart';
  
positive.code:   // so the gap calculation can compensate for it.
    bool _dragStartTransitionComplete = false;
  
    late ScrollableState _scrollable;
    Axis get _scrollDirection => axisDirectionToAxis(_scrollable.axisDirection);
    bool get _reverse =>
  
negative.code: import 'overlay.dart';
  import 'scroll_controller.dart';
  import 'scroll_physics.dart';
  import 'scroll_view.dart';
  import 'scrollable.dart';
  import 'sliver.dart';
  