private Logger getEventRecordingLogger() {
        if (eventRecordingLogger == null) {
            eventRecordingLogger = new EventRecordingLogger(this, eventQueue);
        }
        return eventRecordingLogger;
    }
Return the delegate logger instance if set. Otherwise, return a {@link NOPLogger}
instance.
slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLogger.java