feat(network): 添加 KCP 网络模块

- 新增 GameFrameX.NetWork.Kcp 项目
- 实现 KcpServer、KcpSession、KcpSessionManager 等核心组件
- 添加 KCP 单元测试和集成测试
- 更新解决方案和项目引用

Author: AlianBlank

GameFrameX.NetWork.Kcp/GameFrameX.NetWork.Kcp.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <Import Project="../Version.props" Label="版本号定义"/>
+
+    <PropertyGroup>
+        <Description>GameFrameX.NetWork.Kcp,GameFrameX 框架的 KCP 网络模块.框架文档主页: https://gameframex.doc.alianblank.com</Description>
+        <PackageTags>GameFrameX,Lib,NetWork,Kcp,Server,GameServer</PackageTags>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <!-- 框架依赖 -->
+        <ProjectReference Include="..\GameFrameX.NetWork.Abstractions\GameFrameX.NetWork.Abstractions.csproj"/>
+        <ProjectReference Include="..\GameFrameX.NetWork.Message\GameFrameX.NetWork.Message.csproj"/>
+        <ProjectReference Include="..\GameFrameX.NetWork\GameFrameX.NetWork.csproj"/>
+        <ProjectReference Include="..\GameFrameX.Utility\GameFrameX.Utility.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <!-- SuperSocket UDP 扩展 -->
+        <PackageReference Include="GameFrameX.SuperSocket.Udp" Version="1.2.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <!-- KCP 库 (KumoKyaku/KCP) -->
+        <PackageReference Include="Kcp" Version="2.7.0"/>
+    </ItemGroup>
+
+</Project>

GameFrameX.NetWork.Kcp/IKcpSession.cs

@@ -0,0 +1,54 @@
+using System.Net;
+
+namespace GameFrameX.NetWork.Kcp;
+
+/// <summary>
+/// KCP session interface / KCP 会话接口
+/// </summary>
+public interface IKcpSession
+{
+    /// <summary>
+    /// Conversation ID / 会话 ID
+    /// </summary>
+    uint ConversationId { get; }
+
+    /// <summary>
+    /// Remote endpoint / 远程端点
+    /// </summary>
+    EndPoint RemoteEndPoint { get; }
+
+    /// <summary>
+    /// Is connection active / 连接是否活跃
+    /// </summary>
+    bool IsConnected { get; }
+
+    /// <summary>
+    /// Last active time / 最后活跃时间
+    /// </summary>
+    DateTime LastActiveTime { get; }
+
+    /// <summary>
+    /// Input data received from UDP / 输入从 UDP 接收的数据
+    /// </summary>
+    void Input(ReadOnlySpan<byte> data);
+
+    /// <summary>
+    /// Send data through KCP / 通过 KCP 发送数据
+    /// </summary>
+    int Send(ReadOnlySpan<byte> data);
+
+    /// <summary>
+    /// Receive data from KCP / 从 KCP 接收数据
+    /// </summary>
+    int Recv(Span<byte> buffer);
+
+    /// <summary>
+    /// Try peek receive size / 尝试获取接收大小
+    /// </summary>
+    int PeekSize();
+
+    /// <summary>
+    /// Close connection / 关闭连接
+    /// </summary>
+    void Close();
+}

GameFrameX.NetWork.Kcp/KcpGameAppSession.cs

@@ -0,0 +1,109 @@
+using System.Net;
+using GameFrameX.SuperSocket.Server.Abstractions.Session;
+
+namespace GameFrameX.NetWork.Kcp;
+
+/// <summary>
+/// KCP game app session wrapper / KCP 游戏应用会话包装器
+/// Implements IGameAppSession interface for compatibility with the existing framework
+/// </summary>
+public sealed class KcpGameAppSession : IGameAppSession
+{
+    private readonly IKcpSession _kcpSession;
+    private bool _disposed;
+
+    /// <summary>
+    /// Session unique ID / 会话唯一 ID
+    /// </summary>
+    public string SessionID
+    {
+        get { return _kcpSession.ConversationId.ToString(); }
+    }
+
+    /// <summary>
+    /// Session is connected / 会话是否已连接
+    /// </summary>
+    public bool IsConnected
+    {
+        get { return _kcpSession.IsConnected && !_disposed; }
+    }
+
+    /// <summary>
+    /// Remote endpoint / 远程端点
+    /// </summary>
+    public EndPoint RemoteEndPoint
+    {
+        get { return _kcpSession.RemoteEndPoint; }
+    }
+
+    /// <summary>
+    /// KCP session / KCP 会话
+    /// </summary>
+    public IKcpSession KcpSession
+    {
+        get { return _kcpSession; }
+    }
+
+    /// <summary>
+    /// Creates a new KCP game app session / 创建新的 KCP 游戏应用会话
+    /// </summary>
+    /// <param name="kcpSession">KCP session / KCP 会话</param>
+    public KcpGameAppSession(IKcpSession kcpSession)
+    {
+        _kcpSession = kcpSession ?? throw new ArgumentNullException(nameof(kcpSession));
+    }
+
+    /// <summary>
+    /// Send data to client / 发送数据到客户端
+    /// </summary>
+    /// <param name="data">Data to send / 要发送的数据</param>
+    /// <param name="cancellationToken">Cancellation token / 取消令牌</param>
+    public async ValueTask SendAsync(byte[] data, CancellationToken cancellationToken = default)
+    {
+        if (_disposed || !_kcpSession.IsConnected)
+        {
+            return;
+        }
+
+        _kcpSession.Send(data);
+        await ValueTask.CompletedTask;
+    }
+
+    /// <summary>
+    /// Send data to client / 发送数据到客户端
+    /// </summary>
+    /// <param name="data">Data to send / 要发送的数据</param>
+    /// <param name="cancellationToken">Cancellation token / 取消令牌</param>
+    public async ValueTask SendAsync(ReadOnlyMemory<byte> data, CancellationToken cancellationToken = default)
+    {
+        if (_disposed || !_kcpSession.IsConnected)
+        {
+            return;
+        }
+
+        _kcpSession.Send(data.Span);
+        await ValueTask.CompletedTask;
+    }
+
+    /// <summary>
+    /// Close the session / 关闭会话
+    /// </summary>
+    public void Close()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        _disposed = true;
+        _kcpSession.Close();
+    }
+
+    /// <summary>
+    /// Dispose resources / 释放资源
+    /// </summary>
+    public void Dispose()
+    {
+        Close();
+    }
+}

GameFrameX.NetWork.Kcp/KcpMessagePipelineFilter.cs

@@ -0,0 +1,111 @@
+using System.Buffers;
+using GameFrameX.NetWork.Abstractions;
+
+namespace GameFrameX.NetWork.Kcp;
+
+/// <summary>
+/// KCP message pipeline filter / KCP 消息管道过滤器
+/// </summary>
+public sealed class KcpMessagePipelineFilter
+{
+    /// <summary>
+    /// Parse messages from KCP session / 从 KCP 会话解析消息
+    /// </summary>
+    /// <param name="session">KCP session / KCP 会话</param>
+    /// <returns>List of parsed messages / 解析的消息列表</returns>
+    public List<IMessage> Filter(IKcpSession session)
+    {
+        var messages = new List<IMessage>();
+
+        while (session.IsConnected)
+        {
+            var peekSize = session.PeekSize();
+            if (peekSize <= 0)
+            {
+                break;
+            }
+
+            var buffer = ArrayPool<byte>.Shared.Rent(peekSize);
+            try
+            {
+                var bytesRead = session.Recv(buffer.AsSpan(0, peekSize));
+                if (bytesRead <= 0)
+                {
+                    break;
+                }
+
+                var message = ParseMessage(buffer.AsSpan(0, bytesRead));
+                if (message != null)
+                {
+                    messages.Add(message);
+                }
+            }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
+        }
+
+        return messages;
+    }
+
+    /// <summary>
+    /// Parse a single message from buffer / 从缓冲区解析单条消息
+    /// </summary>
+    /// <param name="buffer">Message buffer / 消息缓冲区</param>
+    /// <returns>Parsed message or null / 解析的消息或 null</returns>
+    public IMessage ParseMessage(ReadOnlySpan<byte> buffer)
+    {
+        if (buffer.Length < sizeof(int))
+        {
+            return null;
+        }
+
+        // Read total length (big-endian)
+        var totalLength = ReadInt32BigEndian(buffer);
+        if (buffer.Length < totalLength)
+        {
+            return null;
+        }
+
+        // Convert to Sequence for decoding
+        var messageData = buffer.Slice(0, totalLength).ToArray();
+        var sequence = new ReadOnlySequence<byte>(messageData);
+
+        return MessageHelper.DecoderHandler.Handler(ref sequence);
+    }
+
+    /// <summary>
+    /// Try parse message header / 尝试解析消息头
+    /// </summary>
+    /// <param name="buffer">Message buffer / 消息缓冲区</param>
+    /// <param name="totalLength">Total message length / 消息总长度</param>
+    /// <returns>True if header was parsed / 如果头部解析成功则返回 true</returns>
+    public bool TryParseHeader(ReadOnlySpan<byte> buffer, out int totalLength)
+    {
+        totalLength = 0;
+
+        if (buffer.Length < sizeof(int))
+        {
+            return false;
+        }
+
+        totalLength = ReadInt32BigEndian(buffer);
+        return totalLength > 0;
+    }
+
+    /// <summary>
+    /// Read int32 in big-endian format / 以大端序读取 int32
+    /// </summary>
+    private static int ReadInt32BigEndian(ReadOnlySpan<byte> buffer)
+    {
+        var value = BitConverter.ToInt32(buffer.Slice(0, 4));
+        if (BitConverter.IsLittleEndian)
+        {
+            // Convert from little-endian to big-endian
+            value = (int)(((uint)value >> 24) | (((uint)value >> 8) & 0xFF00) | (((uint)value << 8) & 0xFF0000) | ((uint)value << 24));
+        }
+
+        return value;
+    }
+}