SignalExample - ReactiveObjC

SignalExample.m

// create signnal
RACSignal *signal = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
    [subscriber sendNext:@"message"];
    return nil;
}];

// subscribe notification
RACDisposable *disposable = [signal subscribeNext:^(id  _Nullable x) {
    NSLog(@"content：%@", x);
}];

// cancel subscribe
[disposable dispose];

// output
// content:message