In AFNetworking Quellcode AFURLSessionManager.m,Warum NSStringFromSelector (@selector (countOfBytesReceived)) für forKeyPath in addObserver verwenden: forKeyPath: Optionen: Kontext in AFNetworking?
(NSURLSessionTask *)task
[task addObserver:self
forKeyPath:NSStringFromSelector(@selector(countOfBytesReceived))
options:NSKeyValueObservingOptionNew
context:NULL];
Warum "NSStringFromSelector (@selector (countOfBytesReceived))" anstelle von @ "countOfBytesReceived".
[Welcher Ansatz für KVC?] (Https://stackoverflow.com/q/15023832/4244136) – Willeke