使用SwiftEntryKit创建的自定义消息视图不显示

Question

我使用SwiftEntryKit制作和显示自定义消息视图。似乎一切正确，但没有出现消息视图！ Xcode版本是：11.3

import UIKit
import SwiftEntryKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = .purple
    }

    @IBAction func btnHandler(_ sender: Any) {
        var attributes = EKAttributes()
        attributes.displayDuration = .infinity
        attributes.position = .bottom
        attributes.entryBackground = .gradient(gradient: .init(colors: [UIColor.red, UIColor.green], startPoint: .zero, endPoint: CGPoint(x: 1, y: 1)))
        attributes.popBehavior = .animated(animation: .init(translate: .init(duration: 0.3), scale: .init(from: 1, to: 0.7, duration: 0.7)))
        attributes.shadow = .active(with: .init(color: .black, opacity: 0.5, radius: 10, offset: .zero))
        attributes.statusBar = .dark
        attributes.scroll = .enabled(swipeable: true, pullbackAnimation: .jolt)
        attributes.positionConstraints.maxSize = .init(width: .constant(value: UIScreen.main.bounds.maxX), height: .intrinsic)
        attributes.lifecycleEvents.didAppear = {
            print("the view appeared!!!")
        }

        let title = EKProperty.LabelContent(text: "titleText", style: .init(font: UIFont.systemFont(ofSize: 14), color: UIColor.black))
        let description = EKProperty.LabelContent(text: "descText", style: .init(font: UIFont.systemFont(ofSize: 12), color: UIColor.black))
        let image = EKProperty.ImageContent(image: UIImage(named: "test")!, size: CGSize(width: 35, height: 35))
        let simpleMessage = EKSimpleMessage(image: image, title: title, description: description)
        let alertMessage = EKAlertMessage(simpleMessage: simpleMessage, buttonBarContent: .init(with: [EKProperty.ButtonContent(label: .init(text: "test", style: .init(font: UIFont.systemFont(ofSize: 10), color: .black)), backgroundColor: .red, highlightedBackgroundColor: .black)], separatorColor: .black, expandAnimatedly: true))
        let alertMessageView = EKAlertMessageView(with: alertMessage)
        print("the button was pressed!!!")
        SwiftEntryKit.display(entry: alertMessageView, using: attributes)
    }

}