private void maybeLogExceptionWarning(Exception e, String message) {
        if (sessionOpen) {
            StringWriter sw = new StringWriter();
            e.printStackTrace(new PrintWriter(sw));
            context.log(log, Level.WARNING, message + ". Exception: " + e.getMessage() + "\n" + sw);
        }
    }
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