code: private Queue<ReadFuture> getReadyReadFutures() {
          Queue<ReadFuture> readyReadFutures =
              (Queue<ReadFuture>) getAttribute(READY_READ_FUTURES_KEY);
          if (readyReadFutures == null) {
              readyReadFutures = new CircularQueue<>();
  
              Queue<ReadFuture> oldReadyReadFutures =
                  (Queue<ReadFuture>) setAttributeIfAbsent(
                          READY_READ_FUTURES_KEY, readyReadFutures);
              if (oldReadyReadFutures != null) {
                  readyReadFutures = oldReadyReadFutures;
              }
          }
          return readyReadFutures;
      }
docs: TODO Add method documentation