Add an asyncKey listener to the directive paylaod on the device-gateway client. #2470

[tommy5oo]

Implement the eventListener

        messageSender.newCall(request)
            .enqueue(
                callback = { ... },
                eventListener = object : MessageSender.EventListener {
                    override fun onAsyncKeyReceived(
                        request: MessageRequest, asyncKey: AsyncKey
                    ) {
                        TODO("Not yet implemented")
                    }
                })
        

[shshshl09]

asyncKey (O) : onAsyncKeyReceived(START) , onSuccess() , onAsyncKeyReceived(END) ,
asyncKey (X) : onSuccess()