public void addAttribute(String alias, AttributeKey<?> attrKey) {
        ensureNotStarted();
        configureExporter(builder -> builder.attr(alias, attrKey));
    }
Adds the specified {@link AttributeKey} to the export list.

@param alias the alias of the attribute to export
@param attrKey the key of the attribute to export
logback/logback12/src/main/java/com/linecorp/armeria/common/logback/RequestContextExportingAppender.java