object_setClass - Type ObjCRuntime.Class which is passed to unmanaged code must have a StructLayout attribute.

gistfile1.txt

using System;
using System.Runtime.InteropServices;
using AVKit;
using Foundation;
using ObjCRuntime;

namespace Xamarin_ios_language_manager
{
    public class ExtendedBundle : NSBundle
    {
        static NSString bundleKey = new NSString("0");

        public override string LocalizedString(string key, string value, string table)
        {
            NSBundle bundle = this.GetProperty<ExtendedBundle>(bundleKey);

            if (bundle != null)
            {
                return bundle.LocalizedString(key, value, table);
            }
            else
            {
                return base.LocalizedString(key, value, table);
            }
        }

        public static void SetLanguage(string currentLanguage)
        {
            try
            {
                
				//static dispatch_once_t onceToken;
				//dispatch_once(&onceToken, ^{
                NSBundleAssociatedObjectExtension.object_setClass(MainBundle.Handle, new Class (typeof(ExtendedBundle)).Handle);
                //});

                var bundle = FromPath(MainBundle.PathForResource("de", "lproj"));
                MainBundle.SetProperty(bundleKey, bundle, NSBundleAssociatedObjectExtension.AssociationPolicy.RetainNonAtomic);

            }
            catch (Exception ex)
            {
                throw (new Exception(ex.Message));
            }
        }
    }


    public static class NSBundleAssociatedObjectExtension
    {
        public enum AssociationPolicy
        {
            Assign = 0,
            RetainNonAtomic = 1,
            CopyNonAtomic = 3,
            Retain = 01401,
            Copy = 01403,
        }

        [DllImport("/usr/lib/libobjc.dylib")]
        public static extern Class object_getClass(IntPtr obj);

        [DllImport("/usr/lib/libobjc.dylib")]
        public static extern Class object_setClass(IntPtr obj, IntPtr cls);

		    [DllImport("/usr/lib/libobjc.dylib")]
        static extern void objc_setAssociatedObject(IntPtr pointer, IntPtr key, IntPtr value, AssociationPolicy policy);

        [DllImport("/usr/lib/libobjc.dylib")]
        static extern IntPtr objc_getAssociatedObject(IntPtr pointer, IntPtr key);

        public static T GetProperty<T>(this NSBundle bundle, NSString propertyKey) where T : NSObject
        {
            var pointer = objc_getAssociatedObject(bundle.Handle, propertyKey.Handle);
            return Runtime.GetNSObject<T>(pointer);
        }

        public static void SetProperty<T>(this NSBundle bundle, NSString propertyKey, T value, AssociationPolicy policy) where T : NSObject
        {
            objc_setAssociatedObject(bundle.Handle, propertyKey.Handle, value.Handle, policy);
        }
    }
}

I am too getting this problem: Type ObjCRuntime.Class which is passed to unmanaged code must have a StructLayout attribute