code: public ServiceFuture<List<ResourceMetricInner>> listMultiRolePoolInstanceMetricsAsync(final String resourceGroupName, final String name, final String instance, final Boolean details, final ListOperationCallback<ResourceMetricInner> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              listMultiRolePoolInstanceMetricsSinglePageAsync(resourceGroupName, name, instance, details),
              new Func1<String, Observable<ServiceResponse<Page<ResourceMetricInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<ResourceMetricInner>>> call(String nextPageLink) {
                      return listMultiRolePoolInstanceMetricsNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Get metrics for a specific instance of a multi-role pool of an App Service Environment.
  Get metrics for a specific instance of a multi-role pool of an App Service Environment.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of the App Service Environment.
  @param instance Name of the instance in the multi-role pool.
  @param details Specify &lt;code&gt;true&lt;/code&gt; to include instance details. The default is &lt;code&gt;false&lt;/code&gt;.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object