private FetchResult fetchStream(long startOffset, long endOffset, int maxBytes) {
        try {
            return stream.fetch(startOffset, endOffset, maxBytes).get();
        } catch (Throwable e) {
            throw new KafkaException(e);
        }
    }
Note that nextOffset in stream here actually represents the physical size (or position).
core/src/main/scala/kafka/log/streamaspect/ElasticTransactionIndex.java