startSelectionPoint property Null safety
The geometry information at the selection start.
This information is used for drawing mobile selection controls. The SelectionPoint.localPosition of the selection start is typically at the start of the selection highlight at where the start selection handle should be drawn.
Can be null if the selection start is offstage, for example, when the selection is outside of the viewport or is kept alive by a scrollable.
final SelectionPoint? startSelectionPoint;