According to the documentation, it seems like AppSync doesn't support BatchUpdateItem (only supports BatchPutItem and BatchGetItem). I have a use case where I want to update a particular attribute of multiple items in a table. Is there an efficient way to do this in AppSync and DynamoDB? I cannot do a batchPutItem because I could be overwriting the item with expired attributes (another client updated an attribute). So the only option is to do UpdateItem one item at a time. I am thinking of having a loop in my iOS app that calls UpdateItem n times. Does this mean that there would be n network rounds? I want to be efficient with my design. Is there anyway I can do all the updates in one network round trip? Thank you.