log/logger.go
func (l *Logger) Infof(format string, args ...interface{}) {
	l.Output(2, LevelInfo, fmt.Sprintf(format, args...))
}
func (l *Logger) Infof(format string, args ...interface{}) {
	l.Output(2, LevelInfo, fmt.Sprintf(format, args...))
}
// Infof records the log with info level