Handle event of NotificationCenter

ReactiveObserverNotificationCenter.m

 @weakify(self);
 [[[[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"NotificationKey"
                                                           object:nil] takeUntil:self.rac_willDeallocSignal] filter:^BOOL(NSNotification *notification) {
     /*
     Validate something for filter
     @strongify(self);
     NSDictionary *userInfo = notification.userInfo;
     return [self.followersViewModel.itemId isEqualToNumber:userInfo[@"itemId"]];
     */
 }] deliverOnMainThread] subscribeNext:^(NSNotification *notification) {
     /*
     BL with data;
     NSDictionary *userInfo = notification.userInfo;
     cell.followerButton.followerButtonMode = ((NSNumber *) userInfo[@"isFollowed"]).boolValue ? TCFollowersButtonModeFollowed : TCFollowersButtonModeFollow;
     */
 }];