anchor.diff:    final List<double> initialFractions;
   
     /// The minimum size each child is allowed to be.
  -  final List<double> minSizes;
  +  final List<double>? minSizes;
   
     /// Splitter widgets to divide [children].
     ///
     /// If this is null, a default splitter will be used to divide [children].
  -  final List<PreferredSizeWidget> splitters;
  +  final List<PreferredSizeWidget>? splitters;
   
     /// The key passed to the divider between children[index] and
     /// children[index + 1].
  
positive.code: // Copyright 2019 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  // @dart=2.9
  
  import 'dart:math' as math;
  
  
negative.code:               // drag action triggers which is't ideal but isn't a launch blocker.
                dragStartBehavior: DragStartBehavior.down,
                child: widget.splitters != null
                    ? widget.splitters![i]
                    : DefaultSplitter(isHorizontal: isHorizontal),
              ),
            ),
  