message: fix: array out-of-bounds error in gaps counter
diff: @@ -42,7 +42,11 @@ impl GapCounts {
  }
  // Count gaps in the internal region
  - let internal = seq[begin..end].iter().filter(|nuc| nuc.is_gap()).count();
  + let internal = if end > begin {
  + seq[begin..end].iter().filter(|nuc| nuc.is_gap()).count()
  + } else {
  + 0
  + };
  let leading = begin;
  let trailing = len - end - 1;
  