sheet property
Only applicable for a self-contained Foil.sheet.
Defaults null unless constructing a Foil.sheet, where default is
new Sheet.
To style a Foil.sheet, provide a Sheet object. A Sheet is a simple
wrapped for any of the potential parameters for a Container.
If no Sheet.color or decoration is provided, this widget will fallback
to rendering as Colors.black in order to provide a mask for this Foil.
Implementation
final Sheet sheet;