@Override
    public void shutdownSourceConnections() {
        log.log(Level.FINE, "Subscriber::cancel");
        synchronized (subscribers) {
            subscribers.values().forEach(Subscriber::cancel);
            subscribers.clear();
        }
        log.log(Level.FINE, "nextConfigFuture.cancel");
        nextConfigFuture.cancel(true);
        log.log(Level.FINE, "nextConfigScheduler.shutdownNow");
        nextConfigScheduler.shutdownNow();
        log.log(Level.FINE, "requester.close");
        requesters.close();
    }
Takes down connection(s) to config sources and running tasks
config-proxy/src/main/java/com/yahoo/vespa/config/proxy/RpcConfigSourceClient.java