Function linear_progress 

pub fn linear_progress(
    id: impl Into<ElementId>,
    label: impl Into<SharedString>,
    fraction: Option<f32>,
    thickness: Pixels,
    muted: bool,
    _window: &mut Window,
    _cx: &mut App,
) -> AnyElement

Material 3 linear progress: the active indicator, a 4px gap, the track and a stop dot at the track’s end. Only a measured fraction draws it; None shows the indeterminate indicator at the same thickness. A paused or stopping process (muted) keeps its fraction in the outline color. The caller-supplied label names the indicator for assistive technology.