boolean sendGetNodeStateReply(int index) {
        for (Iterator<Req> it = waitingRequests.iterator(); it.hasNext(); ) {
             Req r = it.next();
             if (r.request.parameters().size() > 2 && r.request.parameters().get(2).asInt32() == index) {
                 log.log(Level.FINE, () -> "Dummy node " + DummyVdsNode.this + ": Responding to node state reply from controller " + index + " as we received new one");
                 r.request.returnValues().add(new StringValue(nodeState.serialize()));
                 r.request.returnValues().add(new StringValue(hostInfo));
                 r.request.returnRequest();
                 it.remove();
                 ++outdatedStateReplies;
                 return true;
             }
        }
        return false;
    }
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