code: public Observable<ServiceResponse<Page<CsmUsageQuotaInner>>> listUsagesSinglePageAsync(final String resourceGroupName, final String name, final String filter) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (name == null) {
              throw new IllegalArgumentException("Parameter name is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          return service.listUsages(resourceGroupName, name, this.client.subscriptionId(), filter, this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Page<CsmUsageQuotaInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<CsmUsageQuotaInner>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl<CsmUsageQuotaInner>> result = listUsagesDelegate(response);
                          return Observable.just(new ServiceResponse<Page<CsmUsageQuotaInner>>(result.body(), result.response()));
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Gets server farm usage information.
  Gets server farm usage information.
  
  ServiceResponse<PageImpl<CsmUsageQuotaInner>> * @param resourceGroupName Name of the resource group to which the resource belongs.
  ServiceResponse<PageImpl<CsmUsageQuotaInner>> * @param name Name of App Service Plan
  ServiceResponse<PageImpl<CsmUsageQuotaInner>> * @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 PagedList&lt;CsmUsageQuotaInner&gt; object wrapped in {@link ServiceResponse} if successful.