Function push_matched_range 

fn push_matched_range(
    matched_row_ranges: &mut Vec<Range<usize>>,
    pk_filter: &mut dyn PrimaryKeyFilter,
    pk: &[u8],
    start: usize,
    end: usize,
) -> Result<()>

If pk_filter matches pk, records the row range start..end, coalescing it with the previous range when adjacent.