reorderable_grid_view library Null safety

Classes

ReorderableGridView
Usage:
ReorderableItemView
I only need get the pos of other children. How to pass (or access) the pos delegate? Can I pass the pos delegate to all the child(the same to all)? But for now, let's just do it.
ReorderableSliverGridView
ReorderableWrapperWidget

Typedefs

DragWidgetBuilder = Widget Function(int index, Widget child)
Build the drag widget under finger when dragging. The index here represents the index of current dragging widget The child here represents the current index widget
ScrollSpeedController = double Function(int timeInMilliSecond, double overSize, double itemSize)
Control the scroll speed if drag over the boundary. We can pass time here?? timeInMilliSecond is the time passed. overPercentage is the scroll over the boundary percentage overSize is the pixel drag over the boundary itemSize is the drag item size Maybe you need decide the scroll speed by the given param. return how many pixels when scroll in 14ms(maybe a frame). 5 is the default