code: public Observable<Page<ContainerServiceInner>> listByResourceGroupNextAsync(final String nextPageLink) {
          return listByResourceGroupNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<ContainerServiceInner>>, Page<ContainerServiceInner>>() {
                  @Override
                  public Page<ContainerServiceInner> call(ServiceResponse<Page<ContainerServiceInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Gets a list of container services in the specified resource group.
  Gets a list of container services in the specified subscription and resource group. The operation returns properties of each container service including state, orchestrator, number of masters and agents, and FQDNs of masters and agents.
  
  @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;ContainerServiceInner&gt; object