Trait freya::prelude::LayoutMeasurer  
pub trait LayoutMeasurer<Key>where
    Key: NodeKey,{
    // Required method
    fn measure(
        &mut self,
        node_id: Key,
        node: &Node,
        area: &Rect<f32, Measure>,
        parent_area: &Rect<f32, Measure>,
        available_parent_area: &Rect<f32, Measure>
    ) -> Option<Rect<f32, Measure>>;
}