log/logger.go
func (l *Logger) Debugln(args ...interface{}) {
	l.Output(2, LevelDebug, fmt.Sprintln(args...))
}
func (l *Logger) Debugln(args ...interface{}) {
	l.Output(2, LevelDebug, fmt.Sprintln(args...))
}
// Debugln records the log with debug level