Function breathing_dot 

pub fn breathing_dot(
    id: impl Into<ElementId>,
    theme: &Theme,
    color: Hsla,
    size: f32,
    cx: &App,
) -> AnyElement

A dot that breathes, for a place with room for a mark but not a glyph.

The size is the caller’s, because this sits inside layouts that have already decided how much room the mark gets.