pub fn side_by_side(spans: &[(i64, i64)]) -> Vec<(u32, u32)>Expand description
Places spans side by side where they overlap, as (column, columns): each
takes the first column free at its start, and every span of a group of
overlapping ones learns how many columns the group needs. spans are
(start, end), in any unit, an end no earlier than its start.