code: public Observable<Page<ResourceMetricInner>> listMultiRoleMetricsNextAsync(final String nextPageLink) {
          return listMultiRoleMetricsNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<ResourceMetricInner>>, Page<ResourceMetricInner>>() {
                  @Override
                  public Page<ResourceMetricInner> call(ServiceResponse<Page<ResourceMetricInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Get metrics for a multi-role pool of an App Service Environment.
  Get metrics for a multi-role pool of an App Service Environment.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;ResourceMetricInner&gt; object