Unity除了一些基本的数据类型，几乎所有的API都不能在非unity线程中调用，如果项目中有一段很耗时操作，unity可能会出现“假死”。如果这段操作是和unity无关的，我们可以把这个耗时的操作放到子线程中去运行，防止unity假死提高性能，如下面这个伪代码

Function
{
    //这个函数会进行大量文件读写操作
    LoadLocalFile();

    //这个函数是unity函数
    UnityFunction();
}

　　必须保证LoadLocalFile() 不“假死”。怎么做呢？只要把Function放到多线程中，UnityFunction()回到主线程即可

　　网上的做法一般都是借鉴Loom，摘录一个脚本

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
using System.Threading;
using System.Linq;

    public class Loom :MonoBehaviour
    {
        public static int maxThreads = 8;
        static int numThreads;

        private static Loom _current;
        //private int _count;
        public static Loom Current
        {
            get
            {
                Initialize();
                return _current;
            }
        }

        void Awake()
        {
            _current = this;
            initialized = true;
        }

        static bool initialized;

        public static void Initialize()
        {
            if (!initialized)
            {

                if (!Application.isPlaying)
                    return;
                initialized = true;
                var g = new GameObject("Loom");
                _current = g.AddComponent<Loom>();
#if !ARTIST_BUILD
                UnityEngine.Object.DontDestroyOnLoad(g);
#endif
            }

        }
        public struct NoDelayedQueueItem
        {
            public Action<object> action;
            public object param;
        }

        private List<NoDelayedQueueItem> _actions = new List<NoDelayedQueueItem>();
        public struct DelayedQueueItem
        {
            public float time;
            public Action<object> action;
            public object param;
        }
        private List<DelayedQueueItem> _delayed = new List<DelayedQueueItem>();

        List<DelayedQueueItem> _currentDelayed = new List<DelayedQueueItem>();

        public static void QueueOnMainThread(Action<object> taction, object tparam)
        {
            QueueOnMainThread(taction, tparam, 0f);
        }
        public static void QueueOnMainThread(Action<object> taction, object tparam, float time)
        {
            if (time != 0)
            {
                lock (Current._delayed)
                {
                    Current._delayed.Add(new DelayedQueueItem { time = Time.time + time, action = taction, param = tparam });
                }
            }
            else
            {
                lock (Current._actions)
                {
                    Current._actions.Add(new NoDelayedQueueItem { action = taction, param = tparam });
                }
            }
        }

        public static Thread RunAsync(Action a)
        {
            Initialize();
            while (numThreads >= maxThreads)
            {
                Thread.Sleep(100);
            }
            Interlocked.Increment(ref numThreads);
            ThreadPool.QueueUserWorkItem(RunAction, a);
            return null;
        }

        private static void RunAction(object action)
        {
            try
            {
                ((Action)action)();
            }
            catch
            {
            }
            finally
            {
                Interlocked.Decrement(ref numThreads);
            }

        }


        void OnDisable()
        {
            if (_current == this)
            {

                _current = null;
            }
        }



        // Use this for initialization
        void Start()
        {

        }

        List<NoDelayedQueueItem> _currentActions = new List<NoDelayedQueueItem>();

        // Update is called once per frame
        void Update()
        {
            if (_actions.Count > 0)
            {
                lock (_actions)
                {
                    _currentActions.Clear();
                    _currentActions.AddRange(_actions)