"Expected status to be %s, but it was %s",
          oldStatus,
          newStatus);
    }

    boolean compareAndUpdateStatus(Status oldStatus, Status newStatus) {
      return status.compareAndSet(oldStatus, newStatus);
    }

    void close() {
      logger.get().log(FINER, "closing {0}", closingFutureToString());
      closeables.close();
    }