The library didn't support cancelling request, so I just added this feature:
id request = [twitter getStatusesSampleDelimited:nil
stallWarnings:nil
progressBlock:^(id response) {
// ...
} stallWarningBlock:nil
errorBlock:^(NSError *error) {
// ...
}];
// ...
[request cancel]; // when you're done with it
After request cancellation, the error block is called once with a cancellation error.
Let me know if it doesn't fulfil your needs.