anchor.diff:  
   /// A list whose items the user can interactively reorder by dragging.
   ///
  -/// This class is appropriate for views with a small number of
  -/// children because constructing the [List] requires doing work for every
  -/// child that could possibly be displayed in the list view instead of just
  -/// those children that are actually visible.
  -///
  -/// All list items must have a key.
  -///
   /// {@youtube 560 315 https://www.youtube.com/watch?v=3fB1mxOsqJE}
   ///
   /// This sample shows by dragging the user can reorder the items of the list.
  
positive.code: /// ** See code in examples/api/lib/material/reorderable_list/reorderable_list_view.0.dart **
  /// {@end-tool}
  ///
  /// This example demonstrates using the [proxyDecorator] callback to customize the appearance of
  /// a list item while it's being dragged.
  /// {@tool snippet}
  ///
  /// While a drag is underway, the widget returned by the [proxyDecorator] serves as a "proxy" (a substitute)
  /// for the item in the list. The proxy is created with the original list item as its child. The [proxyDecorator]
  /// in this example is similar to the default one except that it changes the proxy item's background color.
  ///
  /// ** See code in examples/api/lib/material/reorderable_list/reorderable_list_view.1.dart **
  /// {@end-tool}
  class ReorderableListView extends StatefulWidget {
    /// Creates a reorderable list from a pre-built list of widgets.
    ///
    /// See also:
    ///
  
negative.code:   /// [ReorderableListView.builder] constructor. Using the [IndexedWidgetBuilder], The
    /// list items are built lazily on demand.
    /// {@tool dartpad}
    ///
    /// ** See code in examples/api/lib/material/reorderable_list/reorderable_list_view.reorderable_list_view_builder.0.dart **
    /// {@end-tool}
  