private Request getNodeState(String nodeType, int nodeIndex, Target connection) {
        Request req = new Request("getNodeState");
        req.parameters().add(new StringValue(nodeType));
        req.parameters().add(new Int32Value(nodeIndex));
        connection.invokeSync(req, timeout());
        return req;
    }
Note: RpcServer is only used in unit tests

@author humbe
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/RpcServerTest.java