code: func (f *Strftime) FormatString(t time.Time) string {
  	const bufSize = 64
  	var b []byte
  	max := len(f.pattern) + 10
  	if max < bufSize {
  		var buf [bufSize]byte
  		b = buf[:0]
  	} else {
  		b = make([]byte, 0, max)
  	}
  	return string(f.format(b, t))
  }
docs: // FormatString takes the time `t` and formats it, returning the
  // string containing the formated data.