code: public Observable<InstanceFailoverGroupInner> createOrUpdateAsync(String resourceGroupName, String locationName, String failoverGroupName, InstanceFailoverGroupInner parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, locationName, failoverGroupName, parameters).map(new Func1<ServiceResponse<InstanceFailoverGroupInner>, InstanceFailoverGroupInner>() {
              @Override
              public InstanceFailoverGroupInner call(ServiceResponse<InstanceFailoverGroupInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates or updates a failover group.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param locationName The name of the region where the resource is located.
  @param failoverGroupName The name of the failover group.
  @param parameters The failover group parameters.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request