I want to activate the camera with an application developed on a cross platform and change the frame rate and shutter speed of the preview screen.

import UIKit
import AVFoundation

classViewController:UIViewController {
    // Creating Objects to Manage Inputs and Outputs from Devices
    var captureSession = AVCaptureSession()

    // Setting the Camera Quality
    func setupCaptureSession(){
        captureSession.sessionPreset=AVCaptureSession.Preset.photo
    }
    // Creating an object that manages the camera device itself
    // Creating a Main Camera Management Object
    varmainCamera —AVCaptureDevice?
    // Creating an In-camera Management Object
    var innerCamera —AVCaptureDevice?
    // Creating a Management Object for Your Camera Device
    varcurrentDevice —AVCaptureDevice?
    
    // Configuring Devices
    func setupDevice(){
        // Camera Device Properties Settings
        let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceType: [AVCaptureDevice.DeviceType.buildInWideAngleCamera], mediaType: AVMediaType.video, position: AVCaptureDevice.Position.unspecified)
        // Obtaining a Camera Device that Meets the Conditions
        let devices = deviceDiscoverySession.devices

        for device in devices {
            if device.position == AVCaptureDevice.Position.back {
                mainCamera=device
            } else if device.position == AVCaptureDevice.Position.front {
                innerCamera=device
            }
        }
        // Set the Startup Camera
        currentDevice=mainCamera
        do{
            !.lockForConfiguration()// Obtained access to the device.
        } catchlet error {
            print(error)
        }
        configureDevice (device:currentDevice!)
    }
    // OBJECT RECEIVING OUTPUT DATA OF CAPTURE
    varphotoOutput —AVCapturePhotoOutput?

    // Configuring Input/Output Data
    func setupInputOutput(){
        do{
            // Initialize input to use the specified device
            let captureDeviceInput=try AVCaptureDeviceInput (device:currentDevice!)
            // Add specified input to session
            captureSession.addInput(captureDeviceInput)
            // Creating an Object to Receive Output Data
            photoOutput = AVCapturePhotoOutput()
            // Formatting Output Files
            photoOutput!.setPreparedPhotoSettingsArray ([AVCapturePhotoSettings (format: [AVVideoCodecKey:AVVideoCodecType.jpeg]], completionHandler:nil)
            captureSession.addOutput(photoOutput!)
        } catch{
            print(error)
        }
    }
    // Layer for preview display
    varcameraPreviewLayer: AVCaptureVideoPreviewLayer?

    // Configuring the Layer for Camera Previews
    func setupPreviewLayer(){
        // Initialize preview layer with specified AVCaptureSession
        self.cameraPreviewLayer=AVCaptureVideoPreviewLayer (session:captureSession)
        // Set the preview layer to display while maintaining the camera capture aspect ratio
        self.cameraPreviewLayer?.videoGravity=AVLayerVideoGravity.resizeAspectFill
        // Set preview layer display orientation
        self.cameraPreviewLayer?connection?.videoOrientation=AVCaptureVideoOrientation.portrait

        self.cameraPreviewLayer?.frame=view.frame
        self.view.layer.insertSublayer(self.cameraPreviewLayer!, at:0)
    }
    
    // Image quality, shutter speed, and iso settings
    func configureDevice (device:AVCaptureDevice) {
        if device.isFocusModeSupported(.continuousAutoFocus){
            device.focusMode=.continuousAutoFocus
        }
        let shutterSpeed=CMTimeMake(value:1, timescale:Int32(slider_value_speed))
        device.setExposeModeCustom(duration:shutterSpeed,iso:Float(slider_value_iso), completionHandler:nil)
        do{
            try device.lockForConfiguration()
            // Frame Rate Settings
            device.activeVideoMinFrameDuration=CMTimeMake(value:1, timescale:Int32(slider_value_frame))
            device.activeVideoMaxFrameDuration=CMTimeMake (value:1, timescale:10)
            device.unlockForConfiguration()
        |catch{}
    }

    @IBOutlet weak var label_frame —UILabel!
    @IBOutlet weak var label_speed —UILabel!
    @IBOutlet weak var label_iso: UILabel!
    
    var slider_value_frame = 10
    var slider_value_speed = 100
    var slider_value_iso = 100
    
    override func viewDidLoad(){
        super.viewDidLoad()
        setupCaptureSession()
        setupDevice()
        setupInputOutput()
        setupPreviewLayer()
        captureSession.startRunning()
    }
    
    @ IBAction func slider_change_frame(_sender:UISlider){
        let sliderValueFrame: Int=Int(sender.value)
        label_frame.text=String(sliderValueFrame)
        slider_value_frame = sliderValueFrame
        print(slider_value_frame)
        configureDevice (device:currentDevice!)
    }
    
    @ IBAction func slider_change_speed(_sender:UISlider){
        let sliderValueSpeed: Int=Int(sender.value)
        label_speed.text=String(sliderValueSpeed)
        slider_value_speed = sliderValueSpeed
        print(slider_value_speed)
        configureDevice (device:currentDevice!)
    }
    
    @ IBAction func slider_change_iso(_sender:UISlider){
        let sliderValueIso: Int=Int(sender.value)
        label_iso.text=String(sliderValueIso)
        slider_value_iso = sliderValueIso
        print(slider_value_iso)
        configureDevice (device:currentDevice!)
    }
}