code: public Observable<Page<ManagedInstanceKeyInner>> listByInstanceNextAsync(final String nextPageLink) {
          return listByInstanceNextWithServiceResponseAsync(nextPageLink)
              .map(new Func1<ServiceResponse<Page<ManagedInstanceKeyInner>>, Page<ManagedInstanceKeyInner>>() {
                  @Override
                  public Page<ManagedInstanceKeyInner> call(ServiceResponse<Page<ManagedInstanceKeyInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Gets a list of managed instance keys.
  
  @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;ManagedInstanceKeyInner&gt; object