code: protected HttpBuilder redirect(URL url) {
          RedirectResponse resp = new RedirectResponse(url);
          RequestContext.setControllerResponse(resp);
          return new HttpBuilder(resp);
      }
docs: Redirects to another URL (usually another site).
  
  @param url absolute URL: <code>http://domain/path...</code>.
  @return {@link HttpSupport.HttpBuilder}, to accept additional information.