@Override
        public int hashCode() {
            return Objects.hash(startedAt, endedAt, progress().map(ProgressToken::serializeToString), state, message);
        }
Returns a copy of this with the given end instant and failure message, in state FAILED.
clustercontroller-reindexer/src/main/java/ai/vespa/reindexing/Reindexing.java