KVOControllerDemo.m

[self.KVOController observe:self
                            keyPath:NSStringFromSelector(@selector(observeObjectName))
                            options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
                              block:^(id  _Nullable observer, id _Nonnull object, NSDictionary<NSString *,id> * _Nonnull change) {
                            //do something
}];