IOS倒计时设置UIButton标题title的抖动问题

例如，在发送验证码后，button状态需要变为disable，每隔一秒显示倒计时时间，仅仅设置
[button setTitle:title forState:UIControlStateDisabled];
或
[button setTitle:title forState:UIControlStateNormal];
是不够的，按钮会一闪一闪的抖动。

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需要同时设置：
button.titleLabel.text = title;
[button setTitle:title forState:UIControlStateDisabled];
或
button.titleLabel.text = title;
[button setTitle:title forState:UIControlStateNormal];