实时音视频（TRTC）通话前如何进行网络测速？

private TRTCCloud trtcCloud;              /// TRTC SDK 实例对象
private TRTCCloudListener trtcListener;    /// TRTC SDK 回调监听

// 创建 trtcCloud 实例
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ....
    trtcListener = new TRTCCloudListenerImpl(this);
    trtcCloud = TRTCCloud.sharedInstance(this);
    trtcCloud.setListener(trtcListener);
}

// 继承 TRTCCloudListener 回调 
static class TRTCCloudListenerImpl extends TRTCCloudListener {
    private WeakReference<TRTCMainActivity> mContext;
    public TRTCCloudListenerImpl(TRTCMainActivity activity) {
        super();
        mContext = new WeakReference<>(activity);
    }
    ....
    // 错误通知是要监听的，错误通知意味着 SDK 不能继续运行了
    @Override
    public void onError(int errCode, String errMsg, Bundle extraInfo) {
        Log.d(TAG, "sdk callback onError");
    }
}

// 创建 trtcCloud 实例
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ....
    trtcListener = new TRTCCloudListenerImpl(this);
    trtcCloud = TRTCCloud.sharedInstance(this);
    trtcCloud.setListener(trtcListener);

    // TRTC SDK 视频通话房间进入所必须的参数
	Intent intent       = getIntent();
	int sdkAppId        = intent.getIntExtra("sdkAppId", 0);
	int roomId          = intent.getIntExtra("roomId", 0);
	String selfUserId   = intent.getStringExtra("userId");
	String userSig      = intent.getStringExtra("userSig");
    // 测速
	trtcCloud.startSpeedTest(sdkAppId, selfUserId, userSig);
}

// 继承 TRTCCloudListener 回调 
static class TRTCCloudListenerImpl extends TRTCCloudListener {
    private WeakReference<TRTCMainActivity> mContext;
    public TRTCCloudListenerImpl(TRTCMainActivity activity) {
        super();
        mContext = new WeakReference<>(activity);
    }
    ....
    // 错误通知是要监听的，错误通知意味着 SDK 不能继续运行了
    @Override
    public void onError(int errCode, String errMsg, Bundle extraInfo) {
        Log.d(TAG, "sdk callback onError");
    }

    /**
     * 服务器测速的回调，SDK 对多个服务器IP做测速，每个IP的测速结果通过这个回调通知
     * @param currentResult 当前完成的测速结果
     * @param finishedCount 已完成测速的服务器数量
     * @param totalCount 需要测速的服务器总数量
     */
    public void onSpeedTest(TRTCCloudDef.TRTCSpeedTestResult currentResult, int finishedCount, int totalCount) {
        Log.i(TAG, "ip = "+currentResult.ip + " | quality = "+currentResult.quality
                + " | upLostRate = "+currentResult.upLostRate + " | upLostRate = "+currentResult.upLostRate
                + " | rtt = "+currentResult.rtt  + " ||| finishedCount = "+finishedCount  + " | totalCount = "+totalCount);
    }
}