void replyToPendingNodeStateRequests() {
        for(Req req : waitingRequests) {
            log.log(Level.FINE, () -> "Dummy node " + this + " answering pending node state request.");
            req.request.returnValues().add(new StringValue(nodeState.serialize()));
            if (req.request.methodName().equals("getnodestate3")) {
                req.request.returnValues().add(new StringValue(hostInfo));
            }
            req.request.returnRequest();
            ++setNodeStateReplies;
        }
        waitingRequests.clear();
    }
Returns the latest system state version received, or empty if none are received yet.
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/DummyVdsNode.java