HarmonyOS 鸿蒙Next 元服务怎么上传文件，使用request.agent.create一直提示错误码13499999

HarmonyOS 鸿蒙Next 元服务怎么上传文件，使用request.agent.create一直提示错误码13499999

import fs from '@ohos.file.fs';
import { uri } from "@kit.ArkTS";
import request from '@ohos.request'; 

const newDataUri = cacheDir + '/test.txt'
let file = fs.openSync(newDataUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
fs.writeSync(file.fd, 'upload file test by API9');
fs.closeSync(file);

const result = new uri.URI(newDataUri);

console.info('path', result.path)
let attachments: Array<request.agent.FormItem> = [{
  name: "test",
  value: [
    {
      filename: "test.txt",
      mimeType: 'application/octet-stream',
      path: result.path,
    },
  ]
}];

let config: request.agent.Config = {
  action: request.agent.Action.UPLOAD,
  url: 'http://127.0.0.1:7788',
  data: attachments,
};

request.agent.create(context, config).then((task: request.agent.Task) => {
  task.start((err: BusinessError) => {
    if (err) {
      console.error(`Failed to start the upload task, Code: ${err.code}  message: ${err.message}`);
      return;
    }
  });
  task.on('progress', async (progress) => {
    console.warn(`/Request upload status ${progress.state}, uploaded ${progress.processed}`);
  })
  task.on('completed', async () => {
    console.warn(`/Request upload completed`);
  })
}).catch((err: BusinessError) => {
  console.error(`Failed to create a upload task, Code: ${err.code}, message: ${err.message}`);
});

无论config怎么配置，都是报错，进入代码最下面的catch中，错误码13499999

文档上很多上传的方法，比如request.uploudFile，元服务都不能用，目前自己发现这个上传途径，接口错误码一直都是13499999（其它错误）

{
  "devices": "development",
  "deviceTypes": [
    "phone",
    "tablet"
  ],
  "development": {
    "addedSysCaps": [
      "SystemCapability.Location.Location.Lite",
      "SystemCapability.FileManagement.UserFileService",
      "SystemCapability.Request.FileTransferAgent"
    ]
  }
}

{
  "module": {
    "name": "entry",
    "type": "entry",
    "description": "$string:module_desc",
    "mainElement": "EntryAbility",
    "deviceTypes": [
      "phone",
      "tablet"
    ],
    "requestPermissions": [{
      "name" : "ohos.permission.INTERNET",
      "reason": "$string:title",
      "usedScene": {
        "abilities": [
          "EntryAbility"
        ],
        "when": "inuse"
      }
    }
    ],
    "deliveryWithInstall": true,
    "installationFree": true,
    "pages": "$profile:main_pages",
    "abilities": [
      {
        "name": "EntryAbility",
        "srcEntry": "./ets/entryability/EntryAbility.ets",
        "description": "$string:EntryAbility_desc",
        "icon": "$media:icon",
        "label": "$string:EntryAbility_label",
        "startWindowIcon": "$media:startIcon",
        "startWindowBackground": "$color:start_window_background",
        "exported": true,
        "skills": [
          {
            "entities": [
              "entity.system.home"
            ],
            "actions": [
              "action.system.home"
            ]
          }
        ]
      }
    ]
  }
}

求指导，等上线