public async Task <IEnumerable <OperationResult <RelationalEntity> > > InsertAndRetrieve(IList <RelationalEntity> entities)
{
var output = new OperationResult <RelationalEntity> [entities.Count];
int index = 0;
var executer = _client.CreateRelationalBatchExecuter(RelationalBatchExecutionMode.Transactional);
foreach (var entity in entities)
{
executer.InsertAndRetrieveEntity(entity, out output[index++]);
}
await executer.ExecuteAsync();
return(output.AsEnumerable());
}