code: public Observable<Page<CsmUsageQuotaInner>> listUsagesAsync(final String resourceGroupName, final String name, final String filter) {
          return listUsagesWithServiceResponseAsync(resourceGroupName, name, filter)
              .map(new Func1<ServiceResponse<Page<CsmUsageQuotaInner>>, Page<CsmUsageQuotaInner>>() {
                  @Override
                  public Page<CsmUsageQuotaInner> call(ServiceResponse<Page<CsmUsageQuotaInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Gets server farm usage information.
  Gets server farm usage information.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of App Service Plan
  @param filter Return only usages/metrics specified in the filter. Filter conforms to odata syntax. Example: $filter=(name.value eq 'Metric1' or name.value eq 'Metric2').
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;CsmUsageQuotaInner&gt; object