How can I insert a UIView into an MSMessage?

Question

I am trying to build an iMessage app that allows a person to press a button which inserts a blue UIView into the iMessage text field. I am not sure how I can get the UIView in the iMessage text field.

I've tried to convert the UIView to a UIImage, then convert that to an MSSticker, however, I need a URL for the sticker and since I created the UIImage in code, I do not have a URL for the path.

Here, I create the UIView:

func createOval() -> UIImage {
    let blueOval = UIView(frame: CGRect(x: 5, y: 0, width: 10, height: 10))
    blueOval.backgroundColor = .black

    let label = UILabel()
    label.text = "Hello"
    blueOval.addSubview(label)

    let image = blueOval.asImage()
    return tagImage
}

The extension that enables the asImage() conversion:

extension UIView {

    func asImage() -> UIImage {
        if #available(iOS 10.0, *) {
            let renderer = UIGraphicsImageRenderer(bounds: bounds)
            return renderer.image { rendererContext in
                layer.render(in: rendererContext.cgContext)
            }
        } else {
            UIGraphicsBeginImageContext(self.frame.size)
            self.layer.render(in:UIGraphicsGetCurrentContext()!)
            let image = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            return UIImage(cgImage: image!.cgImage!)
        }
    }

}

How can I insert that UIView into the iMessage text field?