code: func LogfmtFormat() Format {
  	return FormatFunc(func(r *Record) []byte {
  		common := []interface{}{r.KeyNames.Time, r.Time, r.KeyNames.Lvl, r.Lvl, r.KeyNames.Msg, r.Msg}
  		buf := &bytes.Buffer{}
  		logfmt(buf, append(common, r.Ctx...), 0, false)
  		return buf.Bytes()
  	})
  }
docs: // LogfmtFormat prints records in logfmt format, an easy machine-parseable but human-readable
  // format for key/value pairs.
  //
  // For more details see: http://godoc.org/github.com/kr/logfmt
  //