Using centrifuge-mobile gomobile-generated library from Swift (for iOS development)

ViewController.swift

import UIKit
import Centrifuge

class MessageHandler : NSObject, CentrifugeMessageHandlerProtocol {
    var l: UILabel!
    
    func setLabel(l: UILabel!) {
        self.l = l
    }
    
    func onMessage(_ p0: CentrifugeSub!, p1: CentrifugeMessage!) {
        DispatchQueue.main.async{
            self.l.text = p1.data()
        }
    }
}

class ViewController: UIViewController {
    
    @IBOutlet weak var label: UILabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        label.text = "Connecting..."
        
        DispatchQueue.main.async{
            let creds = CentrifugeNewCredentials(
                "42", "1488055494", "", "24d0aa4d7c679e45e151d268044723d07211c6a9465d0e35ee35303d13c5eeff"
            )
            
            let config = CentrifugeDefaultConfig()
            let eventHandler = CentrifugeNewEventHandler()            
            let url = "ws://localhost:8000/connection/websocket"
            let client = CentrifugeNew(url, creds, eventHandler, config)
            
            do {
                try client?.connect()
            } catch {
                self.label.text = "Error on connect..."
                return
            }
                        
            let subEventHandler = CentrifugeNewSubEventHandler()
            let messageHandler = MessageHandler()
            messageHandler.setLabel(l: self.label)
            subEventHandler?.onMessage(messageHandler)
            
            do {
                try client?.subscribe("channel", events: subEventHandler)
            } catch {
                DispatchQueue.main.async{
                    self.label.text = "Subscribe error"
                }
                return
            }
        }
    } 
}