* must not both be identical to the values given in the first mapping. If only the {@code x}
     * values are identical, the transformation is vertical. If only the {@code y} values are
     * identical, the transformation is horizontal (i.e. the slope is zero).
     */
    public LinearTransformation and(double x2, double y2) {

    private final ImmutableLongArray parent;

    private AsList(ImmutableLongArray parent) {
      this.parent = parent;
    }

    // inherit: isEmpty, containsAll, toArray x2, iterator, listIterator, stream, forEach, mutations

    @Override
    public int size() {
      return parent.length();
    }

    @Override
    public Long get(int index) {

    private final ImmutableIntArray parent;

    private AsList(ImmutableIntArray parent) {
      this.parent = parent;
    }

    // inherit: isEmpty, containsAll, toArray x2, iterator, listIterator, stream, forEach, mutations

    @Override
    public int size() {
      return parent.length();
    }

    @Override
    public Integer get(int index) {

			}
			for rm, x := range v.XferStats {
				x2, ok := v2.XferStats[replication.MetricName(rm)]
				if !ok {
					x2 = replication.XferStats{}
				}
				x2.AvgRate += x.Avg
				x2.CurrRate += x.Curr
				if x.Peak > x2.PeakRate {
					x2.PeakRate = x.Peak
				}
				v2.XferStats[replication.MetricName(rm)] = x2
			}
			sm.Metrics[dID] = v2
		}
	}