updateSegmentIteratorReverse_() {
    const reverse = this.playerInterface_.getPlaybackRate() < 0;
    for (const mediaState of this.mediaStates_.values()) {
      if (mediaState.segmentIterator) {
        mediaState.segmentIterator.setReverse(reverse);
      }
      if (mediaState.segmentPrefetch) {
        mediaState.segmentPrefetch.setReverse(reverse);
      }
    }
    for (const prefetch of this.audioPrefetchMap_.values()) {
      prefetch.setReverse(reverse);
    }
  }
Update the segment iterator direction.

@private