- * This is the id of the chunk where we are writing to if no rotation is
- * pending (rotate_at_seq_num == -1ULL). If a rotation is pending, this
- * is the chunk_id we will have after the rotation. It must be updated
- * atomically with rotate_at_seq_num.
- *
- * Always access with stream lock held.
- *
- * This attribute is not set if the stream is created by a pre-2.11
- * consumer.
+ * `trace_chunk` is the trace chunk to which the file currently
+ * being produced (if any) belongs.