code: public Observable<Page<Resource>> listResourceNextAsync(final String nextPageLink) {
          return listResourceNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<Resource>>, Page<Resource>>() {
                  @Override
                  public Page<Resource> call(ServiceResponse<Page<Resource>> response) {
                      return response.body();
                  }
              });
      }
docs: The List operation gets information about the vaults associated with the subscription.
  
  @param nextPageLink The NextLink from the previous successful call to List operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;Resource&gt; object