gradient property
Customize the visual appearance of this Foil.
If isUnwrapped is true, this Foil's gradient will be
deactivated, smoothly transitioning to an invisible state.
- Override the unwrapped-state
Gradientwith unwrappedGradient.
It is recommended to use a Gradient that starts and ends
with the same Color.
LinearStepsor the otherStepsgradients could handle this aspect.
This Gradient will intrinsically animate to any changed gradient
value by Gradient.lerp over duration and curve.
Using a Roll of Foil
Optionally a Roll may be deployed higher up in the widget tree.
Declare a Roll.gradient to which any descendent Foil may fallback,
though this gradient will override any provided by a Roll.
Pre-rolled Foils
Consider some pre-rolled Foils that come with this package.
The default is Foils.linearLooping if this Foil is not given
a gradient and no ancestral Roll provides one either.

Implementation
final Gradient? gradient;