code: public QuorumCall<AsyncLogger, GetJournalStateResponseProto> getJournalState() {
      Map<AsyncLogger, ListenableFuture<GetJournalStateResponseProto>> calls =
          Maps.newHashMap();
      for (AsyncLogger logger : loggers) {
        calls.put(logger, logger.getJournalState());
      }
      return QuorumCall.create(calls);    
    }
docs: /////////////////////////////////////////////////////////////////////////