Extending NSMutableURLRequest with custom fields

Question

I want to add additional fields to NSMutableURLRequest (for exapmle NSString value requestID) in order to determine correct handler for request when NSURLSession completes it.

Is it legal to create a custom NSMutableURLRequest's subclass to add specific fields? Apple documentation has no additional information about NSMutableURLRequest subclassing.

UPDATE: I discovered that NSMutableURLRequest subclassing is not the best idea: background NSURLSession can't create download task using my custom subclass object: method downloadTaskWithRequest: always returns nil. I think this problem related with mutableCopyWithZone: that called by NSURLSession when it creates download task with request's copy.

Thanks.

Answer 1

I think that if Apple does not provide any warning of subclassing a class, then you can do it.