iOSのインジゲーターができない　Unity側

UIActivityIndicatorView.cs

using UnityEngine;
using System.Collections;
using System.Runtime.InteropServices;

public class UIActivityIndicatorView
{
#if UNITY_IPHONE
    [DllImport("__Internal")]
    private static extern void startSpinner();
#endif
    public static void IPhoneStartSpinner()
    {
#if UNITY_IPHONE
        startSpinner();
#endif
    }

#if UNITY_IPHONE
    [DllImport("__Internal")]
    private static extern void stopSpinner();
#endif
    public static void IPhoneStopSpinner()
    {
#if UNITY_IPHONE
        stopSpinner();
#endif
    }
}