UIControl event handling with blocks

SegmentedControl.m

#import <objc/runtime.h>

// 
//
//

objc_setAssociatedObject(self.segmentedControl, @selector(invoke), ^{
        dispatch_async(dispatch_get_main_queue(), ^{
            // event handler-related code
        });
    }, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    [self.segmentedControl addTarget:objc_getAssociatedObject(self.segmentedControl, @selector(invoke)) action:@selector(invoke) forControlEvents:UIControlEventAllEvents];