Q: Stored properties in swift cannot be converted to properties in objective-c? I encountered a problem when access swift class in objective-c, stored properties in swift cannot be converted to properties in objective-c, such as:
var maxFixedWidth:Float? = defaultMaxWidth {
    didSet{
        self.invalidateIntrinsicContentSize()
        self.setNeedsUpdateConstraints()
    }
}

var itemSpace:Float? = 4 {
    didSet{
        self.invalidateIntrinsicContentSize()
        self.setNeedsUpdateConstraints()
    }
}

These cannot be converted to the following objective-c style properties that should be contained in #import "JDStock-swift.h",
@property (nonatomic, assign) CGFloat maxFixedWidth;

and
@property (nonatomic, assign) CGFloat itemSpace;

It puzzled me for a long time, appreciate for your answers, waiting for you all the time with patient, Thanks!
