deferToBrowser(overrides) {
    debugServer('deferToBrowser', this.url());
    const params = {};
    if (overrides && overrides.url) params.url = overrides.url;
    if (overrides && overrides.method) params.method = overrides.method;
    if (overrides && overrides.headers) params.headers = overrides.headers;
    return this.resolve_(params);
  }
Continues the request with the provided overrides to the url, method or
headers.

@param {{url: (string|undefined), method: (string|undefined),
    headers: (!Object<string, string>|undefined)}|undefined} overrides
Overrides to apply to the request before it hits network.