Function draw 

pub fn draw(
    scene: &mut Scene,
    theme: &Theme,
    bounds: Rect,
    elapsed_seconds: f64,
)

Paint an opaque authentication backdrop inside bounds.

The elapsed time is supplied by the host, making stills and recordings deterministic. Invalid or negative times use the initial composition; long uptimes wrap before trigonometry. Empty or non-finite bounds draw nothing. The base is always opaque, even for a custom theme with translucent tokens.