static equal(reference1, reference2) {
    const ArrayUtils = shaka.util.ArrayUtils;
    const BufferUtils = shaka.util.BufferUtils;

    if (reference1 === reference2) {
      return true;
    } else if (!reference1 || !reference2) {
      return reference1 == reference2;
    } else {
      return reference1.getStartByte() == reference2.getStartByte() &&
          reference1.getEndByte() == reference2.getEndByte() &&
          ArrayUtils.equal(
              reference1.getUris().sort(), reference2.getUris().sort()) &&
          BufferUtils.equal(reference1.getSegmentData(),
              reference2.getSegmentData());
    }
  }
Check if two initSegmentReference have all the same values.
@param {?shaka.media.InitSegmentReference} reference1
@param {?shaka.media.InitSegmentReference} reference2
@return {boolean}