docs: @Override
      public HttpResponse commenceSignup(final FederatedIdentity identity) {
          // store the identity in the session so that we can use this later
          Stapler.getCurrentRequest().getSession().setAttribute(FEDERATED_IDENTITY_SESSION_KEY,identity);
          return new ForwardToView(this,"signupWithFederatedIdentity.jelly") {
              @Override
              public void generateResponse(StaplerRequest req, StaplerResponse rsp, Object node) throws IOException, ServletException {
                  SignupInfo si = new SignupInfo(identity);
                  si.errorMessage = Messages.HudsonPrivateSecurityRealm_WouldYouLikeToSignUp(identity.getPronoun(),identity.getIdentifier());
                  req.setAttribute("data", si);
                  super.generateResponse(req, rsp, node);
              }
          };
      }