constructor(type, tags, segments) {
    /** @const {shaka.hls.PlaylistType} */
    this.type = type;

    /** @const {!Array<!shaka.hls.Tag>} */
    this.tags = tags;

    /** @const {Array<!shaka.hls.Segment>} */
    this.segments = segments || null;
  }
@param {!shaka.hls.PlaylistType} type
@param {!Array<shaka.hls.Tag>} tags
@param {!Array<shaka.hls.Segment>=} segments