pub trait LayoutEngine<E> {
// Required method
fn layout(
&mut self,
mapping: &CoordsMapping,
tree: &WidgetUnit,
) -> Result<Layout, E>;
}
pub trait LayoutEngine<E> {
// Required method
fn layout(
&mut self,
mapping: &CoordsMapping,
tree: &WidgetUnit,
) -> Result<Layout, E>;
}