public void setMaster(boolean isMaster) {
        this.isMaster = isMaster;
    }
This class gets node state updates and timer events and uses these to decide
whether a new cluster state should be generated.

TODO refactor logic out into smaller, separate components. Still state duplication
between ClusterStateGenerator and StateChangeHandler, especially for temporal
state transition configuration parameters.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/StateChangeHandler.java