constructor(thresholdWhenStarving, thresholdWhenSatisfied) {
    const State = shaka.media.BufferingObserver.State;

    /** @private {shaka.media.BufferingObserver.State} */
    this.previousState_ = State.SATISFIED;

    /** @private {!Map<shaka.media.BufferingObserver.State, number>} */
    this.thresholds_ = new Map()
        .set(State.SATISFIED, thresholdWhenSatisfied)
        .set(State.STARVING, thresholdWhenStarving);

    /** @private {number} */
    this.lastRebufferTime_ = 0;
  }
@param {number} thresholdWhenStarving
@param {number} thresholdWhenSatisfied