check.go
func (c *Check) Criticalf(format string, v ...interface{}) {
	c.Exitf(CRITICAL, format, v...)
}
func (c *Check) Criticalf(format string, v ...interface{}) {
	c.Exitf(CRITICAL, format, v...)
}
// Criticalf is a shorthand function which exits the check with status
// CRITICAL and the message provided.