expanded method
Fills a share of remaining space in a Row, Column, or Flex.
flex must be non-negative; zero uses non-flex layout. A positive flex
requires the parent to provide bounded main-axis space.
Keep this wrapper outside render-object wrappers such as Padding:
use child.padding(insets).expanded() inside the flex's children.
Implementation
Expanded expanded({Key? key, int flex = 1}) =>
Expanded(key: key, flex: flex, child: this);