Function sticky_items 

pub fn sticky_items<V, T>(
    entity: Entity<V>,
    compute_fn: impl Fn(&mut V, Range<usize>, &mut Window, &mut Context<'_, V>) -> SmallVec<[T; 8]> + 'static,
    render_fn: impl Fn(&mut V, T, &mut Window, &mut Context<'_, V>) -> SmallVec<[AnyElement; 8]> + 'static,
) -> StickyItems<T>
where
    V: Render,
    T: StickyCandidate + Clone + 'static,