private static String keySetToSortedCsvStr(final Map<String, ?> map) {
        if (NullSafe.isEmptyMap(map)) {
            return "";
        } else {
            return setToSortedCsvStr(map.keySet());
        }
    }
Handler class that forwards the request to a URL.
stroom-pipeline/src/main/java/stroom/pipeline/writer/HTTPAppender.java