由於需求變化，今天臨時寫了一個“令牌桶”類。他的功能是：存放令牌並管理令牌的過期時間

不多說了直接上程式碼：

    public class TokenBucket
    {
        /// <summary>
        /// 令牌過期時間
        /// 預設60秒
        /// </summary>
        public int TokenTimeOutTrick { get; set; } = 60000;
        private readonly ConcurrentDictionary<string, CancellationTokenSource> buket = new
 
 ConcurrentDictionary<string, CancellationTokenSource>();
        /// <summary>
        /// 新增令牌
        /// </summary>
        /// <param name="token"></param>
        /// <returns></returns>
        public bool AddToken(string token)
        {
            CancellationTokenSource tokenSource 
 
= new CancellationTokenSource();
            var result = buket.TryAdd(token, tokenSource);
            if (result)
            {
#pragma warning disable CS4014 // 由於此呼叫不會等待，因此在呼叫完成前將繼續執行當前方法
                TokenTimeOut(token, tokenSource);
#pragma warning restore CS4014 // 由於此呼叫不會等待，因此在呼叫完成前將繼續執行當前方法
            }
            
 
return result;
        }
        /// <summary>
        /// 令牌過期
        /// </summary>
        /// <param name="token"></param>
        /// <param name="tokenSource"></param>
        /// <returns></returns>
        private async Task TokenTimeOut(string token, CancellationTokenSource tokenSource)
        {
            CancellationToken cancellationToken = tokenSource.Token;
            await Task.Delay(TokenTimeOutTrick, cancellationToken);
            buket.TryRemove(token, out CancellationTokenSource cts);
            if (cts != null)
                cts.Dispose();
        }
        /// <summary>
        /// 刪除令牌
        /// </summary>
        /// <param name="token"></param>
        public void ReomveToken(string token)
        {
            var remove = buket.TryRemove(token, out CancellationTokenSource cts);
            try
            {
                if (remove)
                {
                    cts.Cancel();
                }
            }
            catch { }
            finally
            {
                if (cts != null)
                    cts.Dispose();
            }
        }
        /// <summary>
        /// 令牌是否存在
        /// </summary>
        /// <param name="token"></param>
        /// <returns></returns>
        public bool HasToken(string token)
        {
            return buket.ContainsKey(token);
        }
    }