code: public Observable<ServiceResponse<Page<FirewallRuleInner>>> listFirewallRulesWithServiceResponseAsync(final String resourceGroupName, final String accountName) {
          return listFirewallRulesSinglePageAsync(resourceGroupName, accountName)
              .concatMap(new Func1<ServiceResponse<Page<FirewallRuleInner>>, Observable<ServiceResponse<Page<FirewallRuleInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<FirewallRuleInner>>> call(ServiceResponse<Page<FirewallRuleInner>> page) {
                      String nextPageLink = page.body().nextPageLink();
                      if (nextPageLink == null) {
                          return Observable.just(page);
                      }
                      return Observable.just(page).concatWith(listFirewallRulesNextWithServiceResponseAsync(nextPageLink));
                  }
              });
      }
docs: Lists the Data Lake Store firewall rules within the specified Data Lake Store account.
  
  @param resourceGroupName The name of the Azure resource group that contains the Data Lake Store account.
  @param accountName The name of the Data Lake Store account from which to get the firewall rules.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;FirewallRuleInner&gt; object