code: public Observable<ServiceResponse<Page<CertificateIssuerItem>>> getCertificateIssuersWithServiceResponseAsync(final String vaultBaseUrl, final Integer maxresults) {
          return getCertificateIssuersSinglePageAsync(vaultBaseUrl, maxresults)
              .concatMap(new Func1<ServiceResponse<Page<CertificateIssuerItem>>, Observable<ServiceResponse<Page<CertificateIssuerItem>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<CertificateIssuerItem>>> call(ServiceResponse<Page<CertificateIssuerItem>> page) {
                      String nextPageLink = page.body().nextPageLink();
                      if (nextPageLink == null) {
                          return Observable.just(page);
                      }
                      return Observable.just(page).concatWith(getCertificateIssuersNextWithServiceResponseAsync(nextPageLink));
                  }
              });
      }
docs: List certificate issuers for a specified key vault.
  The GetCertificateIssuers operation returns the set of certificate issuer resources in the specified key vault. This operation requires the certificates/manageissuers/getissuers permission.
  
  @param vaultBaseUrl The vault name, for example https://myvault.vault.azure.net.
  @param maxresults Maximum number of results to return in a page. If not specified the service will return up to 25 results.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;CertificateIssuerItem&gt; object