check.go
func (c *Check) Exitf(status Status, format string, v ...interface{}) {
	info := fmt.Sprintf(format, v...)
	c.AddResult(status, info)
	c.Finish()
}
func (c *Check) Exitf(status Status, format string, v ...interface{}) {
	info := fmt.Sprintf(format, v...)
	c.AddResult(status, info)
	c.Finish()
}
// Exitf takes a status plus a format string, and a list of
// parameters to pass to Sprintf. It then immediately outputs and exits.