protected void handleSuccess(HttpServletRequest request, HttpServletResponse response,
UpgradeInfo upgradeInfo, TyrusUpgradeResponse upgradeResponse) throws IOException, ServletException {
TyrusHttpUpgradeHandler handler = request.upgrade(TyrusHttpUpgradeHandler.class);
Writer servletWriter = servletWriterHelper.newInstance(handler);
handler.preInit(upgradeInfo, servletWriter, request.getUserPrincipal() != null);
response.setStatus(upgradeResponse.getStatus());
for (Map.Entry<String, List<String>> entry : upgradeResponse.getHeaders().entrySet()) {
response.addHeader(entry.getKey(), Utils.getHeaderFromList(entry.getValue()));
}