logger.go
func (l *logger) Infoln(vals ...interface{}) {
	l.mut.Lock()
	defer l.mut.Unlock()
	s := fmt.Sprintln(vals...)
	l.logger.Output(2, "INFO: "+s)
	l.callHandlers(LevelInfo, s)
}
func (l *logger) Infoln(vals ...interface{}) {
	l.mut.Lock()
	defer l.mut.Unlock()
	s := fmt.Sprintln(vals...)
	l.logger.Output(2, "INFO: "+s)
	l.callHandlers(LevelInfo, s)
}
// Infoln logs a line with an INFO prefix.