RPBroadcastSampleHandler any method not getting called

I want to implement screen sharing functionality like skype(when app is in background then also it will share screen of iPhone), and for that i am using broadcast extension.

Here its my code in my viewcontroller.swift

    import UIKit
    import ReplayKit
    @available(iOS 12.0, *)
    class ViewController: UIViewController {

        var broadcastPicker: RPSystemBroadcastPickerView?
        var broadcastSession : NSObject?
        override func viewDidLoad() {
            super.viewDidLoad()
            let kPickerFrame = CGRect(x: 100.0, y: 100.0, width: 100.0, height: 100.0)
            broadcastPicker = RPSystemBroadcastPickerView(frame: kPickerFrame)
            broadcastPicker?.backgroundColor = UIColor.green
            broadcastPicker!.preferredExtension = "com.sharescreen.Recoder"
            view.addSubview(broadcastPicker!)

            extensionContext?.loadBroadcastingApplicationInfo(completion: {
            (bundleID, displayName, appIcon) in

            })

        }
   }

and when i click on RPSystemBroadcastPickerView i am getting popup for start broadcast and when i start broadcast any extension method is not calling.

This is my extension class

    class SampleHandler: RPBroadcastSampleHandler {


    var session : VTCompressionSession?
    override func broadcastStarted(withSetupInfo setupInfo: [String : NSObject]?) {
        // User has requested to start the broadcast. Setup info from the UI extension can be supplied but optional.

    }

    override func broadcastPaused() {
        // User has requested to pause the broadcast. Samples will stop being delivered.
    }

    override func broadcastResumed() {
        // User has requested to resume the broadcast. Samples delivery will resume.
    }

    override func broadcastFinished() {
        // User has requested to finish the broadcast.
    }

    override func processSampleBuffer(_ sampleBuffer: CMSampleBuffer, with sampleBufferType: RPSampleBufferType) {
        switch sampleBufferType {
        case RPSampleBufferType.video:
            // Handle video sample buffer

            break
        case RPSampleBufferType.audioApp:
            // Handle audio sample buffer for app audio
            break
        case RPSampleBufferType.audioMic:
            // Handle audio sample buffer for mic audio
            break
        @unknown default:
            // Handle other sample buffer types
            fatalError("Unknown type of sample buffer")
        }
    }
}

Can you please help me to find out that what i am doing wrong?

from RPBroadcastSampleHandler any method not getting called