docs: public static synchronized RecoveryDirector instance() {
          if (tc.isEntryEnabled())
              Tr.entry(tc, "instance");
  
          if (_instance == null) {
              _instance = new RecoveryDirectorImpl();
          }
  
          if (tc.isEntryEnabled())
              Tr.exit(tc, "instance", _instance);
          return _instance;
      }