private void populateStateStrings(ClusterStateBundle state) {
        states.put(BASELINE, state.getBaselineClusterState().toString());
        var derivedStates = state.getDerivedBucketSpaceStates().entrySet().stream()
                .collect(Collectors.toMap(
                        entry -> entry.getKey(),
                        entry -> entry.getValue().getClusterState().toString()));
        states.putAll(derivedStates);
    }
Represents the absolute cluster states (baseline + derived) for a given version
as well as the relative diffs (baseline + derived) since the previous version.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/ClusterStateHistoryEntry.java