public static ClusterStateHistoryEntry makeFirstEntry(ClusterStateBundle state, long time) {
        return new ClusterStateHistoryEntry(state, time);
    }
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