code: func (b *Bitmap) SliceRange(start, end uint64) []uint64 {
  	var a []uint64
  	itr := b.Iterator()
  	itr.Seek(start)
  	for v, eof := itr.Next(); !eof && v < end; v, eof = itr.Next() {
  		a = append(a, v)
  	}
  	return a
  }
docs: // SliceRange returns a slice of integers between [start, end).