@Override
    public boolean storeStartTimestamps(Map<Node, Long> timestamps) {
        if (timestamps == null) timestamps = new TreeMap<>();
        StringBuilder sb = new StringBuilder();
        for (Node n : timestamps.keySet()) {
            Long timestamp = timestamps.get(n);
            sb.append(n.toString()).append(':').append(timestamp).append('\n');
        }
        byte[] val = sb.toString().getBytes(utf8);
        try{
            context.log(log, Level.FINE, () -> "Storing start timestamps at '" + paths.startTimestamps() + "'");
            session.setData(paths.startTimestamps(), val, -1);
            return true;
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } catch (Exception e) {
            maybeLogExceptionWarning(e, "Failed to store start timestamps in ZooKeeper");
            return false;
        }
    }
If this is called, we assume we're in shutdown situation, or we are doing it because we need a new session.
Thus we only need to free up resources, no need to notify anyone.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/ZooKeeperDatabase.java