docs: public Metrics extendMultipleDimensionsIncludeRoot(final String... dimensionsGroup) {
          final String[] dimensionsGroupWithRoot = Arrays.copyOf(dimensionsGroup, dimensionsGroup.length + 1);
          // root dimensions is equivalent to extend root dimensions with no new dimension
          dimensionsGroupWithRoot[dimensionsGroup.length] = getRootDimensionsString();
          return new MetricsGroup(this, dimensionsGroupWithRoot);
      }