public FlushResult and(final FlushResult another) {
      return switch (this) {
        case FLUSHED_ALL -> another == HAS_MORE_TO_FLUSH ?
                            HAS_MORE_TO_FLUSH :
                            FLUSHED_ALL;
        case HAS_MORE_TO_FLUSH -> HAS_MORE_TO_FLUSH;
        case NOTHING_TO_FLUSH_NOW -> another;
      };
    }
public FlushResult and(final FlushResult another)