notifyPeriodDuration(startTime, endTime) {
    this.notifyMinSegmentStartTime(startTime);
    if (endTime != Infinity && !this.isLive()) {
      this.maxSegmentEndTime_ = Math.max(this.maxSegmentEndTime_, endTime);
    }
  }
Gives PresentationTimeline an startTime and endTime of the period.
This should be only set for Dash.

@param {number} startTime
@param {number} endTime
@export