ViewController.swift

func rtcEngine(_ engine: AgoraRtcEngineKit, didJoinedOfUid uid: UInt, elapsed: Int) {
    let videoView = UIView()
    videoView.tag = Int(uid)
    videoView.backgroundColor = UIColor.purple
    let videoCanvas = AgoraRtcVideoCanvas()
    videoCanvas.uid = uid
    videoCanvas.view = videoView
    videoCanvas.renderMode = .hidden
    agoraKit.setupRemoteVideo(videoCanvas)
    stackView.addArrangedSubview(videoView)
}

internal func rtcEngine(_ engine: AgoraRtcEngineKit, didOfflineOfUid uid:UInt, reason:AgoraUserOfflineReason) {
    guard let view = stackView.arrangedSubviews.first(where: { (view) -> Bool in
        return view.tag == Int(uid)
    }) else { 
        return 
    }
    stackView.removeArrangedSubview(view)
}