code: protected Response performRequest(String url,
  			Map<String, String> additionalHeaders) throws IOException {
  		if (accessToken == null) {
  			throw new UnauthorizedException("Access token has not yet been requested");
  		}
  		URL u = new URL(url);
  		return auth.request(u, Method.GET, accessToken, additionalHeaders);
  	}
docs: Performs a request
  @param url the URL to query
  @param additionalHeaders additional HTTP request headers (may be null)
  @return the response
  @throws IOException if the request was not successful