public void markUnread() {
        if (dataBlockGroup == null) {
            throw new IllegalStateException("DataBlock is not loaded yet.");
        }
        lastAccessTimestamp = time.milliseconds();
        if (unreadCnt.get() == UNREAD_INIT) {
            unreadCnt.set(1);
        } else {
            int old = unreadCnt.getAndIncrement();
            if (old == 0) {
                // observe
                listener.markUnread(this);
            }
        }
    }
Complete the data loading with exception
s3stream/src/main/java/com/automq/stream/s3/cache/blockcache/DataBlock.java