@Override
    public Iterator<Appender<ILoggingEvent>> iteratorForAppenders() {
        return aai.iteratorForAppenders();
    }
Stores the specified {@link RequestContextExporterBuilder} customizer to be lazily applied when
the exporter is built.
logback/logback12/src/main/java/com/linecorp/armeria/common/logback/RequestContextExportingAppender.java