async request(configOrUrl, config) {
    try {
      return await this._request(configOrUrl, config);
    } catch (err) {
      if (err instanceof Error) {
        let dummy = {};

        Error.captureStackTrace ? Error.captureStackTrace(dummy) : (dummy = new Error());

        // slice off the Error: ... line
        const stack = dummy.stack ? dummy.stack.replace(/^.+\n/, '') : '';
        try {
          if (!err.stack) {
            err.stack = stack;
            // match without the 2 top stack lines
          } else if (stack && !String(err.stack).endsWith(stack.replace(/^.+\n.+\n/, ''))) {
            err.stack += '\n' + stack;
          }
        } catch (e) {
          // ignore the case where "stack" is an un-writable property
        }
      }

      throw err;
    }
  }
Dispatch a request

@param {String|Object} configOrUrl The config specific for this request (merged with this.defaults)
@param {?Object} config

@returns {Promise} The Promise to be fulfilled