function makeIprTimeline(duration, delay) {
    const now = Date.now() / 1000;
    const timeline = makePresentationTimeline(
        /* static= */ false, duration, /* start= */ now,
        /* availability= */ Infinity, /* max= */ 10,
        /* clock= */ 0, delay || 0);
    expect(timeline.isLive()).toBe(false);
    expect(timeline.isInProgress()).toBe(true);
    return timeline;
  }
Creates a IPR PresentationTimeline.

@param {number} duration
@param {number=} delay
@return {shaka.media.PresentationTimeline}