public Optional<Instant> lastReadiedAt() {
        if ( ! enabled) return Optional.empty();
        if (clusters.values().stream().anyMatch(cluster -> ! cluster.pending().isEmpty())) return Optional.empty();
        return clusters.values().stream()
                       .flatMap(cluster -> cluster.ready().values().stream())
                       .map(Reindexing.Status::ready)
                       .max(naturalOrder());
    }
Instant at which reindexing in this was last readied, unless no reindexing is still pending, in which case this is empty.
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationReindexing.java