constructor(ref, estimateId, groupId, isInitSegment, refPosition) {
    /** @type {shaka.media.SegmentReference|shaka.media.InitSegmentReference} */
    this.ref = ref;

    /** @type {number} */
    this.estimateId = estimateId;

    /** @type {number} */
    this.groupId = groupId;

    /** @type {boolean} */
    this.isInitSegment = isInitSegment;

    /** @type {number} */
    this.refPosition = refPosition;
  }
@param {shaka.media.SegmentReference|shaka.media.InitSegmentReference} ref
@param {number} estimateId
@param {number} groupId
@param {boolean} isInitSegment
@param {number} refPosition