code: func (s *sequence) toString() string {
  	var nextBlock string
  	if s.next == nil {
  		nextBlock = "end"
  	} else {
  		nextBlock = s.next.toString()
  	}
  	return fmt.Sprintf("(0x%x, %d)->%s", s.block, s.count, nextBlock)
  }
docs: // String returns a string representation of the block sequence starting from this block