glg.go
func LogFunc(f func() string) error {
	if isModeEnable(LOG) {
		return glg.out(LOG, "%s", f())
	}
	return nil
}
func LogFunc(f func() string) error {
	if isModeEnable(LOG) {
		return glg.out(LOG, "%s", f())
	}
	return nil
}
// LogFunc outputs Log level log returned from the function