Function draw_spans 

pub fn draw_spans(spans: &[Span<'_>], area: Rect, buf: &mut Buffer) -> u16

Draw wrapped spans at the top of area, and answer the rows they used.

The block counterpart to draw_line: that one takes a run that is one line by construction and wraps it because it might not fit, and this one takes a run with authored breaks in it and keeps them.