code: public Observable<Void> renewAsync(String resourceGroupName, String domainName) {
          return renewWithServiceResponseAsync(resourceGroupName, domainName).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Renew a domain.
  Renew a domain.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param domainName Name of the domain.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.