.NET for AndroidでSurfaceViewのANativeWindowを取得する

.NET for Android（旧：Xamarin.Android）でVulkanを動かすのにSurfaceViewのANativeWindowを取得する必要がある。.NETだとANativeWindow_fromSurfaceをP/Invokeで簡単に呼び出せるのが便利。

[DllImport("android", CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr ANativeWindow_fromSurface(IntPtr env, IntPtr surface);

public static IntPtr GetANativeWindowFromSurfaceView(SurfaceView surfaceView) {
    Surface surface = surfaceView.Holder.Surface;
    IntPtr surfacePtr = JNIEnv.ToLocalJniHandle(surface);
    IntPtr aNativeWindow = ANativeWindow_fromSurface(JNIEnv.Handle, surfacePtr);
    return aNativeWindow;
}