Function compute_leaf_layout 

pub fn compute_leaf_layout<MeasureFunction>(
    inputs: LayoutInput,
    style: &impl CoreStyle,
    resolve_calc_value: impl Fn(*const (), f32) -> f32,
    measure_function: MeasureFunction,
) -> LayoutOutput
where
    MeasureFunction: FnOnce(Size<Option<f32>>, Size<AvailableSpace>) -> Size<f32>,

Compute the size of a leaf node (node with no children)

A definite inputs.available_space is treated as the space available to the node’s border box: the caller is expected to have already subtracted the node’s margins from it.