public static Supervisor createRealSupervisor() {
        return new Supervisor(new Transport("rpc-communicator")).setDropEmptyBuffers(true);
    }
Responsible for doing RPC requests to storage nodes.
This class is not thread-safe.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/rpc/RPCCommunicator.java