This approach is extremely unsafe. If I change the selected segment before the request completes, the data will be delivered to the wrong parsing method (I've actually tried that and it causes the app to crash). A better approach is to use the convention to retrieve the object which generated the event as a parameter to its delegate, so you can use it to identify the data. 

In this case you could do something like:

```Objective-C
- (void)request(RequestType *)request didCompleteWithData:(DataType *)data {
    if (request *is equal to something*) {
        do something...
    } else ...
```