private void configureExporter(Consumer<RequestContextExporterBuilder> customizer) {
        requireNonNull(customizer, "customizer");
        this.customizer = this.customizer.andThen(customizer);
    }
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