}
    }
    
    public WitnessHeartbeatResponse heartbeat(WitnessHeartbeatRequest request) throws IOException {
        try {
            WitnessHeartbeatStub stub = new WitnessHeartbeatStub(request);
            handle.sendrecv(stub);
            return stub.getResponse();
        } catch (Exception e) {
            throw new IOException("Witness heartbeat RPC failed", e);
        }