Function NavigationRail 

pub fn NavigationRail(
    selected_index: usize,
    items: Vec<NavRailItem>,
    header: Option<View>,
    fab: Option<View>,
    config: NavigationRailConfig,
) -> View

M3 Navigation Rail - a compact vertical navigation sidebar.

Typically placed on the left side of the screen. Contains navigation items (icon + label) with animated selection indicator.