code: public Observable<ServiceResponse<Page<DiagnosticCategoryInner>>> listSiteDiagnosticCategoriesWithServiceResponseAsync(final String resourceGroupName, final String siteName) {
          return listSiteDiagnosticCategoriesSinglePageAsync(resourceGroupName, siteName)
              .concatMap(new Func1<ServiceResponse<Page<DiagnosticCategoryInner>>, Observable<ServiceResponse<Page<DiagnosticCategoryInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<DiagnosticCategoryInner>>> call(ServiceResponse<Page<DiagnosticCategoryInner>> page) {
                      String nextPageLink = page.body().nextPageLink();
                      if (nextPageLink == null) {
                          return Observable.just(page);
                      }
                      return Observable.just(page).concatWith(listSiteDiagnosticCategoriesNextWithServiceResponseAsync(nextPageLink));
                  }
              });
      }
docs: Get Diagnostics Categories.
  Get Diagnostics Categories.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param siteName Site Name
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;DiagnosticCategoryInner&gt; object