code: public Observable<Page<ManagedClusterInner>> listByResourceGroupNextAsync(final String nextPageLink) {
          return listByResourceGroupNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<ManagedClusterInner>>, Page<ManagedClusterInner>>() {
                  @Override
                  public Page<ManagedClusterInner> call(ServiceResponse<Page<ManagedClusterInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists managed clusters in the specified subscription and resource group.
  Lists managed clusters in the specified subscription and resource group. The operation returns properties of each managed cluster.
  
  @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;ManagedClusterInner&gt; object