static forSingleSegment(startTime, duration, uris) {
    const reference = new shaka.media.SegmentReference(
        /* startTime= */ startTime,
        /* endTime= */ startTime + duration,
        /* getUris= */ () => uris,
        /* startByte= */ 0,
        /* endByte= */ null,
        /* initSegmentReference= */ null,
        /* presentationTimeOffset= */ startTime,
        /* appendWindowStart= */ startTime,
        /* appendWindowEnd= */ startTime + duration);
    return new shaka.media.SegmentIndex([reference]);
  }
Create a SegmentIndex for a single segment of the given start time and
duration at the given URIs.

@param {number} startTime
@param {number} duration
@param {!Array<string>} uris
@return {!shaka.media.SegmentIndex}
@export