如何使用接口下载文件

import { BusinessError, request } from '@kit.BasicServicesKit'; 
 
let config: request.agent.Config = { 
  action: request.agent.Action.DOWNLOAD, 
  url: 'http://xxxx', 
  title: 'taskResumeTest', 
  description: 'Sample code for resume the download task', 
  mode: request.agent.Mode.BACKGROUND, 
  overwrite: false, 
  method: "GET", 
  data: "", 
  saveas: "./", 
  network: request.agent.Network.CELLULAR, 
  metered: false, 
  roaming: true, 
  retry: true, 
  redirect: true, 
  index: 0, 
  begins: 0, 
  ends: -1, 
  gauge: false, 
  precise: false, 
  token: "it is a secret" 
}; 
request.agent.create(getContext(), config, (err: BusinessError, task: request.agent.Task) => { 
  if (err) { 
    console.error(`Failed to create a download task, Code: ${err.code}, message: ${err.message}`); 
    return; 
  } 
  console.info(`Succeeded in creating a download task. result: ${task.config}`); 
});