sraSpanDup(const sraSpan *src) {
  sraSpan *span;
  if (!src) return NULL;
  span = sraSpanCreate(src->start, src->end, src->subspan);
  return span;
}
sraSpanDup(const sraSpan *src) {
  sraSpan *span;
  if (!src) return NULL;
  span = sraSpanCreate(src->start, src->end, src->subspan);
  return span;
}