code: public Observable<DomainInner> beginCreateOrUpdateAsync(String resourceGroupName, String domainName, DomainInner domainInfo) {
          return beginCreateOrUpdateWithServiceResponseAsync(resourceGroupName, domainName, domainInfo).map(new Func1<ServiceResponse<DomainInner>, DomainInner>() {
              @Override
              public DomainInner call(ServiceResponse<DomainInner> response) {
                  return response.body();
              }
          });
      }
docs: Create a domain.
  Asynchronously creates a new domain with the specified parameters.
  
  @param resourceGroupName The name of the resource group within the user's subscription.
  @param domainName Name of the domain
  @param domainInfo Domain information
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the DomainInner object