有時候我們想要階段性執行操作，比如日誌輸出，不考慮資料丟失的問題，我們不想每個日誌都去寫一次硬碟，而是一段時間後一次性寫入，以及其他類似的需求

程式碼如下

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using System.Linq;
using System.Collections.Concurrent;
using System.Text;

 
namespace ConsoleApp {
    class Program {
        static void Main(string[] args) {
            Logger logger = new Logger();
            StageWaitTask<string> stageWaitTask = new StageWaitTask<string>((ps) => {
                StringBuilder sb = new StringBuilder();
                
 
foreach (var p in ps) {
                    sb.Append(p + ",");
                }
                logger.Info(sb.ToString());  //日誌每次輸出浪費資源，所以我要累積一段時間的資料後，階段性執行
            },2000);
            for (int i = 0; i < 99; i++) {
                stageWaitTask.PutParam(i.ToString());  //將日誌要資料的資訊扔到到階段性任務物件裡
                Thread.Sleep(100
 
);
            }
            Console.ReadKey();
        }
    }
    public class Logger {
        public void Info(string msg) {
            Console.WriteLine(msg);
        }
    }
    /// <summary>
    /// 階段性等待任務
    /// </summary> 
    public class StageWaitTask<T> {
        /// <summary>
        /// 引數的佇列
        /// </summary>
        private Queue<T> queue = new Queue<T>();
        private readonly object _lock = new object();
        private Timer timer = null;
        private bool free = true;
        /// <summary>
        /// 等待的動作
        /// </summary>
        private readonly Action<IList<T>> action = null;
        /// <summary>
        /// 等待的時長
        /// </summary>
        private readonly int milliseconds = 0;
        /// <summary>
        /// 傳入等待執行的函式和時間間隔
        /// </summary> 
        public StageWaitTask(Action<IList<T>> action,int milliseconds) {
            timer = new Timer(Run);
            this.action = action;
            this.milliseconds = milliseconds;
        }
        /// <summary>
        /// 向佇列中放參數
        /// </summary>
        public void PutParam(T data) {
            lock (_lock) {
                queue.Enqueue(data);
                if (free == true) {  //只有在空閒的狀態下才允許下次等待，同一時間只允許一個延遲觸發
                    free = false;
                    timer.Change(milliseconds,Timeout.Infinite);  //等待milliseconds毫秒後執行Run
                }
            }
        }
        /// <summary>
        /// 等待執行的函式
        /// </summary> 
        private void Run(object arg) {
            lock (_lock) {
                action(queue.ToList()); //從佇列中拿去所有引數資料，執行外部傳入的階段性邏輯
                queue.Clear();  //清空佇列
                free = true; //置為空閒，可以觸發下一次等待
            }
        }
    }
}