问核心情节CPTBorderedLayer没有动画

EN

CGRect originalBounds = annotation.contentLayer.bounds;
CGRect expandedBounds = annotation.contentLayer.bounds;
expandedBounds.size.width *= 1.5f;
expandedBounds.size.height *= 1.5f;

CABasicAnimation* boundsAnimation = [CABasicAnimation animationWithKeyPath:@"bounds"];
boundsAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
boundsAnimation.fromValue = [NSValue valueWithCGRect:originalBounds];
boundsAnimation.toValue = [NSValue valueWithCGRect:expandedBounds];
boundsAnimation.duration = 1.0f;
boundsAnimation.removedOnCompletion = NO;

[annotation.contentLayer addAnimation:boundsAnimation forKey:@"bounds"];