docs: private static void restoreInvocationSubject(SubjectCookie cookie) {
          try {
              if (cookie.token != null) {
                  // We sync'ed the subject's identity to the thread under setInvocationSubject. 
                  // Now restore the previous identity using the token returned when we sync'ed.
                  ThreadIdentityManager.resetChecked(cookie.token);
              }
          } catch (ThreadIdentityException e) {
              throw new SecurityException(e);
          } finally {
              SubjectManagerService sms = smServiceRef.getService();
              if (sms != null) {
                  sms.setInvocationSubject(cookie.subject);
              }
          }
      }