code: public Completable rollbackAndRestartStream(final short partition, final long seqno) {
      return stopStreaming(partition)
          .andThen(Completable.create(new Completable.OnSubscribe() {
            @Override
            public void call(CompletableSubscriber subscriber) {
              sessionState().rollbackToPosition(partition, seqno);
              subscriber.onCompleted();
            }
          }))
          .andThen(startStreaming(partition));
    }
docs: Helper method to rollback the partition state and stop/restart the stream.
  <p>
  The stream is stopped (if not already done). Then:
  <p>
  The rollback seqno state is applied. Note that this will also remove all the failover logs for the partition
  that are higher than the given seqno, since the server told us we are ahead of it.
  <p>
  Finally, the stream is restarted again.
  
  @param partition the partition id
  @param seqno the sequence number to rollback to