timer for tracking the users doodling coordinates

.swift

    public func setup () {
        resetDoodleRect()
        
        lastTouchTimestamp = 0
        
        if #available(iOS 10.0, *) {
            trackTimer = Timer.scheduledTimer(withTimeInterval: 0.5, repeats: true, block: {
                timer in
                
                let now = Date().timeIntervalSince1970
                
                if Int(self.lastTouchTimestamp!) > 0 && now - self.lastTouchTimestamp! > 1 {
                    self.drawDoodlingRect(context: self.context)
                }
            })
        } else {}
    }