@Override
        public ContentCluster getCluster() { return cluster; }
Move tasks that are dependent on the most recently generated state being published into
a completion queue with a dependency on the provided version argument. Once that version
has been ACKed by all distributors in the system, those tasks will be marked as completed.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java