Map<Object, Object> userDataSReg = new HashMap<>();
//userData.put("email", "user@example.com");
SRegResponse sregResp = SRegResponse.createSRegResponse(sregReq, userDataSReg);
// (alternatively) manually add attribute values
sregResp.addAttribute("email", email);
response.addExtension(sregResp);
}
} else {
throw new UnsupportedOperationException("TODO");
}