code: public ServiceFuture<DataMigrationServiceInner> getByResourceGroupAsync(String groupName, String serviceName, final ServiceCallback<DataMigrationServiceInner> serviceCallback) {
          return ServiceFuture.fromResponse(getByResourceGroupWithServiceResponseAsync(groupName, serviceName), serviceCallback);
      }
docs: Get DMS Service Instance.
  The services resource is the top-level resource that represents the Data Migration Service. The GET method retrieves information about a service instance.
  
  @param groupName Name of the resource group
  @param serviceName Name of the service
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object