I am using an xib to display custom info window in google maps. The info window is not getting shown

My XIB Class With Self initialization

final class MarkerWindow: UIView {
    @IBOutlet var containerView: UIView!
    @IBOutlet weak var imgUser: UIImageView!
    @IBOutlet weak var lblUserName: UILabel!
    @IBOutlet weak var lblEmergency: UILabel!
    @IBOutlet weak var lblDistance: UILabel!
    @IBOutlet weak var vwEmergency: UIView!
    @IBOutlet weak var widthConst: NSLayoutConstraint!
    @IBOutlet weak var heightConst: NSLayoutConstraint!
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.initSubViews()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        self.initSubViews()
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        vwEmergency.CornerRadius = (vwEmergency.frame.height) / 2
    }

    private func initSubViews() {
    let nib = UINib(nibName: String(describing: type(of: self)), bundle: Bundle(for: type(of: self)))
        nib.instantiate(withOwner: self, options: nil)
        containerView.translatesAutoresizingMaskIntoConstraints = false
        widthConst.constant = 388
        heightConst.constant = 100
        addSubview(containerView)
        self.addConstraints()
    }
    
    private func addConstraints() {
        NSLayoutConstraint.activate([
            self.topAnchor.constraint(equalTo: containerView.topAnchor),
            self.leadingAnchor.constraint(equalTo: containerView.leadingAnchor),
            self.trailingAnchor.constraint(equalTo: containerView.trailingAnchor),
            self.bottomAnchor.constraint(equalTo: containerView.bottomAnchor)
        ])
    }
}

Delegate Method Called

func mapView(_ mapView: GMSMapView, markerInfoWindow marker: GMSMarker) -> UIView? {
    let customInfoWindow = MarkerWindow()
    return customInfoWindow
}

Outlets Connected in XIB Class Given Through File Owner
When Trying to initialize xib from View Controller by other methods Getting Error Bad Access Code - 2.

Solution

I called xib in viewDidLoad() instead of info window method.

var customView = MarkerWindow()
customView = MarkerWindow(frame: CGRect(x: 0, y: 0, width: 388, height: 100))

Then I return the topmost level UIView in the method as:

func mapView(_ mapView: GMSMapView, markerInfoWindow marker: GMSMarker) -> UIView? { 
    return customView.containerView
}

And, I can see my xib view now. I also removed the MarkerWindow class from topmost view of xib. Now it is only in FileOwner.