@Override
    public String toString() {
        return "DefaultElasticStreamSlice{" +
                ", streamId=" + stream.streamId() +
                ", slice=" + sliceRange() +
                ", nextOffset=" + nextOffset() +
                ", sealed=" + sealed +
                '}';
    }
the real start offset of this segment in the stream.
core/src/main/scala/kafka/log/streamaspect/DefaultElasticStreamSlice.java