如何对 initXXXX 这系列方法进行 methods swizzling？

- (id)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame]) {
        // do something ...
    }
    return self;
}

- (id)swizzled_initWithFrame:(CGRect)frame
{
    // This is the confusing part (article explains this line).
    id result = [self swizzled_initWithFrame:frame];

    // Safe guard: do we have an UIView (or something that has a layer)?
    if ([result respondsToSelector:@selector(layer)]) {
        // Get layer for this view.
        CALayer *layer = [result layer];
        // Set border on layer.
        layer.borderWidth = 2;
        layer.borderColor = [[UIColor redColor] CGColor];
    }

    // Return the modified view.
    return result;
}


+ (void)load
{
    Method original, swizzle;

    // Get the "- (id)initWithFrame:" method.
    original = class_getInstanceMethod(self, @selector(initWithFrame:));

    // Get the "- (id)swizzled_initWithFrame:" method.
    swizzle = class_getInstanceMethod(self, @selector(swizzled_initWithFrame:));

    // Swap their implementations.
    method_exchangeImplementations(original, swizzle);
}