pub(crate) fn acc_range( a: Option<Range<u64>>, b: Option<Range<u64>>, ) -> Option<Range<u64>>
Computes the covering range of two optional ranges
For example acc_range(Some(7..9), Some(1..3)) = Some(1..9)
acc_range(Some(7..9), Some(1..3)) = Some(1..9)