public Optional<EffectiveMeta> last() {
        try {
            return Optional.ofNullable(effectiveMetas.last());
        } catch (NoSuchElementException e) {
            return Optional.empty();
        }
    }
@return The {@link EffectiveMeta} with the most recent effectiveTimeMs
stroom-meta/stroom-meta-api/src/main/java/stroom/meta/api/EffectiveMetaSet.java