MainThreadDispatcher.cs

using System;
using System.Collections.Generic;
using UnityEngine;

namespace ModUpdater
{
    /// <summary>
    /// Attach this MonoBehaviour to a persistent GameObject so that
    /// background threads can queue work onto Unity's main thread.
    /// </summary>
    public class MainThreadDispatcher : MonoBehaviour
    {
        private static MainThreadDispatcher instance;
        private static readonly Queue<Action> queue = new Queue<Action>();
        private static readonly object lockObj = new object();

        /// <summary>
        /// Lazily creates a hidden, DontDestroyOnLoad GameObject
        /// the first time anything needs to dispatch.
        /// </summary>
        public static void Initialise()
        {
            if (instance != null) return;

            var go = new GameObject("[ModUpdater_Dispatcher]");
            DontDestroyOnLoad(go);
            go.hideFlags = HideFlags.HideAndDontSave;
            instance = go.AddComponent<MainThreadDispatcher>();
        }

        /// <summary>
        /// Enqueue an action to run on the next Update() frame.
        /// Safe to call from any thread.
        /// </summary>
        public static void Enqueue(Action action)
        {
            if (action == null) return;
            lock (lockObj)
            {
                queue.Enqueue(action);
            }
        }

        private void Update()
        {
            lock (lockObj)
            {
                while (queue.Count > 0)
                {
                    Action action = queue.Dequeue();
                    try
                    {
                        action.Invoke();
                    }
                    catch (Exception ex)
                    {
                        Debug.LogError($"[ModUpdater] Dispatcher error: {ex}");
                    }
                }
            }
        }
    }
}