Function to check camera access permissions.

checkForPermissions.swift

    //        MARK: Checks for user's permisions
    public func checkForPermissions() {
      
        switch AVCaptureDevice.authorizationStatus(for: .video) {
        case .authorized:
            // The user has previously granted access to the camera.
            break
        case .notDetermined:
            /*
             The user has not yet been presented with the option to grant
             video access. Suspend the session queue to delay session
             setup until the access request has completed.
             */
            sessionQueue.suspend()
            AVCaptureDevice.requestAccess(for: .video, completionHandler: { granted in
                if !granted {
                    self.setupResult = .notAuthorized
                }
                self.sessionQueue.resume()
            })
            
        default:
            // The user has previously denied access. 
            // Store this result, create an alert error and tell the UI to show it.
            setupResult = .notAuthorized
            
            DispatchQueue.main.async {
                self.alertError = AlertError(title: "Camera Access", message: "SwiftCamera doesn't have access to use your camera, please update your privacy settings.", primaryButtonTitle: "Settings", secondaryButtonTitle: nil, primaryAction: {
                        UIApplication.shared.open(URL(string: UIApplication.openSettingsURLString)!,
                                                  options: [:], completionHandler: nil)
                    
                }, secondaryAction: nil)
                self.shouldShowAlertView = true
                self.isCameraUnavailable = true
                self.isCameraButtonDisabled = true
            }
        }
    }

Hello! Thanks for this helpful function. Could I ask what type of queue is self.sesionQueue and how it's used in this context?