app.Use(async (context,next) =>
            {
                context.Items["isExist"] = true;
                await next.Invoke();
            });

            //在之后的管道查詢值
            app.Run(async (context) =>
            {
                await context.Response.WriteAsync("Is Exist:"+context.Items["isExist"]);
            });

services.AddDistributedMemoryCache();
            services.AddSession(options =>
            {
                options.Cookie.Name = "Test.Session";
                options.IdleTimeout = TimeSpan.FromSeconds(10);
            });

services.AddSession(options =>
            {
                options.Cookie.Name = "Test.Session";
                options.IdleTimeout = TimeSpan.FromSeconds(10);
            });

public interface ISession
    {
        //
        // 摘要:
        //     Indicate whether the current session has loaded.
        bool IsAvailable { get; }
        //
        // 摘要:
        //     A unique identifier for the current session. This is not the same as the session
        //     cookie since the cookie lifetime may not be the same as the session entry lifetime
        //     in the data store.
        string Id { get; }
        //
        // 摘要:
        //     Enumerates all the keys, if any.
        IEnumerable<string> Keys { get; }

        //
        // 摘要:
        //     Remove all entries from the current session, if any. The session cookie is not
        //     removed.
        void Clear();
        //
        // 摘要:
        //     Store the session in the data store. This may throw if the data store is unavailable.
        Task CommitAsync(CancellationToken cancellationToken = default(CancellationToken));
        //
        // 摘要:
        //     Load the session from the data store. This may throw if the data store is unavailable.
        Task LoadAsync(CancellationToken cancellationToken = default(CancellationToken));
        //
        // 摘要:
        //     Remove the given key from the session if present.
        //
        // 參數(shù):
        //   key:
        void Remove(string key);
        //
        // 摘要:
        //     Set the given key and value in the current session. This will throw if the session
        //     was not established prior to sending the response.
        //
        // 參數(shù):
        //   key:
        //
        //   value:
        void Set(string key, byte[] value);
        //
        // 摘要:
        //     Retrieve the value of the given key, if present.
        //
        // 參數(shù):
        //   key:
        //
        //   value:
        bool TryGetValue(string key, out byte[] value);
    }

HttpContext.Session.SetInt32("key",123);
            HttpContext.Session.GetInt32("key");

/// <summary> 
        /// 將一個object對象序列化，返回一個byte[]         
        /// </summary> 
        /// <param name="obj">能序列化的對象</param>         
        /// <returns></returns> 
        public static byte[] ObjectToBytes(object obj)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                IFormatter formatter = new BinaryFormatter(); formatter.Serialize(ms, obj); return ms.GetBuffer();
            }
        }
        /// <summary> 
        /// 將一個序列化后的byte[]數(shù)組還原         
        /// </summary>
        /// <param name="Bytes"></param>         
        /// <returns></returns> 
        public static object BytesToObject(byte[] Bytes)
        {
            using (MemoryStream ms = new MemoryStream(Bytes))
            {
                IFormatter formatter = new BinaryFormatter(); return formatter.Deserialize(ms);
            }
        }