code: public Observable<List<Domain>> getDomainsAsync() {
          return getDomainsWithServiceResponseAsync().map(new Func1<ServiceResponse<List<Domain>>, List<Domain>>() {
              @Override
              public List<Domain> call(ServiceResponse<List<Domain>> response) {
                  return response.body();
              }
          });
      }
docs: Get a list of the available domains.
  
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;Domain&gt; object