Unity如何判断网络连接类型

[code]csharpcode：

using UnityEngine;
using System.Collections;

public class Test : MonoBehaviour {

    string s;
	// Use this for initialization
	void Start () {
        if (Application.internetReachability == NetworkReachability.ReachableViaCarrierDataNetwork)
        {
            s = "2G/3G/4G";
        }
        else if (Application.internetReachability == NetworkReachability.ReachableViaLocalAreaNetwork)
        {
            s = "wifi";
        }
        else if (Application.internetReachability == NetworkReachability.NotReachable)
        {
            s = "duan wang";
        }
        

	}
	
	// Update is called once per frame
	void Update () {
	    
	}

    void OnGUI()
    {
        GUILayout.Label(s);
    }
}