关于扩展属性

[fanlilinSaber]

1. @Property (nonatomic, assign, readonly, getter=hasFinished) BOOL finished; 可否暴露这个属性 我想在自定义的时候更多扩展
2. @Property (assign, nonatomic) CGFloat verticalMargin UI_APPEARANCE_SELECTOR; 可否新增这个属性，因为默认 margin 是调整左右上下的间距，定制化的时候 我想可以单独调整上下的间距
   [topSpacer addConstraint:[NSLayoutConstraint constraintWithItem:topSpacer attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.f constant:self.verticalMargin]];
   [bottomSpacer addConstraint:[NSLayoutConstraint constraintWithItem:bottomSpacer attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.f constant:self.verticalMargin]];