perfdata.go
func (p PerfDatum) String() string {
	val := fmtPerfFloat(p.value)
	value := fmt.Sprintf("%s=%s%s", p.label, val, p.unit)
	value += fmt.Sprintf(";%s;%s", fmtThreshold(p.warn), fmtThreshold(p.crit))
	value += fmt.Sprintf(";%s;%s", fmtThreshold(p.min), fmtThreshold(p.max))
	return value
}
func (p PerfDatum) String() string {
	val := fmtPerfFloat(p.value)
	value := fmt.Sprintf("%s=%s%s", p.label, val, p.unit)
	value += fmt.Sprintf(";%s;%s", fmtThreshold(p.warn), fmtThreshold(p.crit))
	value += fmt.Sprintf(";%s;%s", fmtThreshold(p.min), fmtThreshold(p.max))
	return value
}
// String returns the string representation of a PerfDatum, suitable for
// check output.