RPC Howto

class RpcChannel : public google::protobuf::RpcChannel
{
  void CallMethod(...) override
  {
    // do some task, then dispatch to RpcClientCore.
  }
  // Non-virtual new method (fast service)
  void CallMethod(uint16_t serviceId, const FastRequest &req, FastResponse *resp,
                  Closure *done);
};

void Write(RpcController *ctrl, const ReadRequestPB &req, ReadResponsePB *resp)
{
  // protobuf framework
  RpcChannel channel; // channel can be cached to reduce cpu.
  mRpcClient->OpenChannel(addr, &channel);
  IoService::Stub stub(&channel);
  SyncClosure sync;
  stub.Write(ctrl, req, resp, done, &sync);
  sync.Wait();
  // parse response and/or update ctrl.
}

void Write(RpcController *ctrl, const FastRequest &req, FastResponse *resp)
{
  // protobuf framework
  RpcChannel channel; // channel can be cached to reduce cpu.
  mRpcClient->OpenChannel(addr, &channel);
  IoService::Stub stub(&channel);
  SyncClosure sync;
  stub.Write(ctrl, req, resp, done, &sync);
  sync.Wait();
  // parse response and/or update ctrl.
}

void Start()
{
  RpcServer server;
  server.RegisterService(&mIoService);
  server.Start(); // start receive packets from network.
}

void Write(RpcController *ctrl,
           const ReadRequestPB &req, ReadResponsePB *resp,
           Closure *done)
{
  // Write Task:
  // parse and check request
  // then do Write task, then fill response.
  int result = doWriteTask(ctrl, req, resp);
  resp->set_result(result);
  done->Run();
}