code: func (p *Progress) Print(optionals ...bool) {
  	stream := os.Stderr
  	if len(optionals) > 0 {
  		if optionals[0] {
  			stream = os.Stdout
  		}
  	}
  	f := bufio.NewWriter(stream)
  	defer f.Flush()
  	f.WriteString(fmt.Sprintf("% *s\r", p.sOutput, ""))
  	f.WriteString(p.String() + "\r")
  }
docs: // Print Progress structure on stderr or stdout if the first optional argument
  // is true