节点快速错误：“发送后无法设置标头”

Question

我定义了这样的快速路线：

qiniuRoute.js

module.exports = function (app) {
  const qiniu = require('../controllers/qiniuController')
  app.route('/upload')
    .post(qiniu.uploadFile);
}

qiniuController.js

function uploadFile(req, res) {
  const form = new formidable.IncomingForm();

  form.parse(req, function (err, fields, files) {

    console.log('receive');

    console.log(files.file);
    const localFile = files.file.path;
    const config = new qiniu.conf.Config();
    const formUploader = new qiniu.form_up.FormUploader(config);
    const putExtra = new qiniu.form_up.PutExtra();
    const key = files.file.name;
    const uploadToken = renderUploadToken(req, res);

    // fileupload
    formUploader.putFile(uploadToken, key, localFile, putExtra, function (respErr,
      respBody, respInfo) {
      if (respErr) {
        throw respErr;
        res.json({
          error: respErr.error
        })
        return;
      }
      console.log(respInfo)
      if (respInfo.statusCode == 200) {
        console.log(respBody);
        res.json(respBody)
      } else {
        console.log(respInfo.statusCode);
        console.log(respBody);
      }
    });
  });

};

但是当我发出文件上传请求时出现错误显示“发送后无法设置标头”，似乎我多次响应客户端但我已经返回错误句柄。我还有另一个猜测，导致我的fileupload是异步函数，这意味着我的回调函数不能res.json？