starlight如何支持brpc协议的attachment

[hirocube]

Java客户端和C++服务端通信，如何在请求时添加 byte attachment？即brpc c++客户端中的 cntl->request_attachment()

C++ 客户端代码：

void SendRequest(Request *request) {
    butil::IOBuf buf = pack(request);
    
    auto *cntl = new brpc::Controller;

    // add packed bytes as request attachment
    cntl->request_attachment().swap(buf);

    cntl->set_timeout_ms(10);
    cntl->set_max_retry(0);
    
    ReadRequest req;
    auto *resp = new ReadResponse;
    QueryService_Stub stub(request->GetChannel());
    stub.ReadTable(
        cntl, &req, resp,
        brpc::NewCallback(....);
     // more code ....
}

服务端代码：

void QueryService::Read(
    google::protobuf::RpcController* cntl_base,
    ReadRequest* request,
    ReadResponse* response,
    google::protobuf::Closure* done) {
    brpc::ClosureGuard done_guard(done);
    brpc::Controller* cntl = static_cast<brpc::Controller*>(cntl_base);

    // read attachment and unpack
    if (!Unpack(cntl->request_attachment())) {
        cntl->SetFailed(UNPACK_ERROR, "unpack fail");
        return;
    }

    // more code ....
}

在brpc-java-v3中可以通过RpcContext.getContext().setRequestBinaryAttachment(ByteBuffer)来实现，但这个接口在starlight中没有了。如果使用starlight，这个功能怎么实现，API是哪个？