private ElasticLogMeta generateLogMeta() {
        Map<String, Stream> streams = streamManager.streams();
        List<ElasticStreamSegmentMeta> segmentList = segments.values().stream()
            .sorted()
            .map(ElasticLogSegment::meta)
            .collect(Collectors.toList());
        return logMeta(streams, segmentList);
    }
Calculate trim offset of each stream.

@return stream trim offset map, key is stream name, value is trim offset.
core/src/main/scala/kafka/log/streamaspect/ElasticLogSegmentManager.java