https://docs.unity3d.com/ScriptReference/NetworkReachability.html
인터넷 연결상태를 확인할수 있다.
if (Application.internetReachability.Equals(NetworkReachability.NotReachable)){
// Disconnect Internet
}
else if (Application.internetReachability.Equals( NetworkReachability.ReachableViaCarrierDataNetwork)) {
// Connect Internet Data network
}
else if (Application.internetReachability.Equals(NetworkReachability.ReachableViaLocalAreaNetwork)){
// Connect WIFI
}