HarmonyOS 鸿蒙Next IPC sendMessageRequest使用callback出错

这样子写会出现 result == undefined

而不用Callback则正常，是怎么回事呢？

function sendRequestCallback(err: Error, result: rpc.RequestResult) {
  if(result == undefined){
    promptAction.showToast({
      message: "undefined"
    });
    return;
  }

  try {
    if (result.errCode != 0) {
      return;
    }
    // 从result.reply里读取结果
    let msg = `Respond: ${result.reply.readString()}`;
    promptAction.showToast({
      message: msg
    });
  } finally {
    result.data.reclaim();
    result.reply.reclaim();
  }
}


let data = rpc.MessageSequence.create();
data.writeString("Test Service");
let reply = rpc.MessageSequence.create();
let option = new rpc.MessageOption();
this.proxy.sendMessageRequest(0x0001, data, reply, option, sendRequestCallback);