public class SnowFlake
    {
        /// <summary>
        /// 總機器位數
        /// </summary>
        private static readonly int WorkBits = 5;
        /// <summary>
        /// 自增序列號位數
        /// </summary>
        private static readonly int SequenceBits = 16;
        /// <summary>
        /// 序列號最大值 0開始 
        
 
/// </summary>
        private static readonly long SequenceMax = 1L << SequenceBits;
        /// <summary>
        /// 伺服器最大值
        /// </summary>
        private static readonly long WorkMax = 1L << WorkBits;
        /// <summary>
        /// 當前機器號 0-WorkMax
        /// </summary>
 

        private static long CurrentWorkId = 0;
        /// <summary>
        /// 加鎖物件
        /// </summary>
        private readonly object objlock = new object();
        /// <summary>
        /// 記錄上次時間戳
        /// </summary>
        private static long LastTime;
        /// <summary>
        ///
 
 當前序列號 0開始
        /// </summary>
        private static long CurrentSequence = -1;
        public SnowFlake(int _CurrentWorkId)
        {
            CurrentWorkId = _CurrentWorkId;
            Console.WriteLine(SequenceMax);
        }
        /// <summary>
        /// 自定義時間戳
        /// </summary>
        /// <returns></returns>
        private long GetTime()
        {
            return (long)(DateTime.UtcNow - new DateTime(2020, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
        }


        /// <summary>
        /// 獲取ID
        /// </summary>
        /// <returns></returns>
        public long NextId()
        {
            lock (objlock)
            {
                if (CurrentWorkId >= WorkMax)
                {
                    throw new Exception($"機器碼不能大於最大機器碼值{WorkMax}");
                }
                var time = GetTime();
                //同秒內序列號自增
                if (time == LastTime)
                {
                    //序列號超出最大 等待下一個時間點
                    if (CurrentSequence >= SequenceMax)
                    {
                        //等待下一個時間點
                        while (time == LastTime)
                        {
                            time = GetTime();
                        }
                        CurrentSequence = -1;
                        LastTime = time;
                    }
                }
                else
                {
                    //不同秒 重新自增
                    CurrentSequence = -1;
                    LastTime = time;
                }
                CurrentSequence++;

                //Console.WriteLine(DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss fff"));
                //Console.WriteLine(CurrentSequence);

                var num = (WorkBits + SequenceBits);
                return time << num | CurrentWorkId << SequenceBits | CurrentSequence;
            }
        }

       
    }

以上程式碼為個人理解寫法，若有不足，請指正。

實際的演算法為 1個0bit+41bit時間戳+10bit機器碼+12bit序列號; 最終得到的是64bit的二進位制 也就是能支援int64最大值，可支援單機器每秒400多W的ID生成;

但js的最大Number型別是53bit，且常用系統也達不到這麼多併發，所以參考了廖雪峰老師的意見 修改為

32bit的秒級時間戳(現計算結果為31bit)+5bit的機器碼+16bit的序列號 共53bit，而且時間戳未使用1970預設演算法，採用了自定義年份，以上程式碼可支援最大2^5=32個機器 每臺機器2^16=65535個ID生成。

SnowFlake演算法其他理解參考https://www.cnblogs.com/firstdream/p/9055771.html，

檢視int的bit可用Convert.ToString(num, 2);檢視

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