contentTop property Null safety
final
The vertical distance from the Scaffold's origin to the top of Scaffold.body.
This is useful in a FloatingActionButtonLocation designed to place the FloatingActionButton at the top of the screen, while keeping it below the Scaffold.appBar.
The Scaffold.body is laid out with respect to minInsets already. This means that a FloatingActionButtonLocation does not need to factor in EdgeInsets.top of minInsets when aligning a FloatingActionButton to contentTop.
Implementation
final double contentTop;