diff --git a/Realtime/Conversation/LCIMConversation.cs b/Realtime/Conversation/LCIMConversation.cs
index 8f19470..95ceb64 100644
--- a/Realtime/Conversation/LCIMConversation.cs
+++ b/Realtime/Conversation/LCIMConversation.cs
@@ -4,22 +4,36 @@ using System.Threading.Tasks;
 using System.Linq;
 using System.Collections.ObjectModel;
 using LeanCloud.Storage;
-using LeanCloud.Storage.Internal.Codec;
 
 namespace LeanCloud.Realtime {
+    /// <summary>
+    /// 普通对话
+    /// </summary>
     public class LCIMConversation {
+        /// <summary>
+        /// 对话 Id
+        /// </summary>
         public string Id {
             get; internal set;
         }
 
+        /// <summary>
+        /// 是否唯一
+        /// </summary>
         public bool Unique {
             get; internal set;
         }
 
+        /// <summary>
+        /// 唯一 Id
+        /// </summary>
         public string UniqueId {
             get; internal set;
         }
 
+        /// <summary>
+        /// 对话名称
+        /// </summary>
         public string Name {
             get {
                 return this["name"] as string;
@@ -29,42 +43,69 @@ namespace LeanCloud.Realtime {
             }
         }
 
+        /// <summary>
+        /// 创建者 Id
+        /// </summary>
         public string CreatorId {
             get; set;
         }
 
+        /// <summary>
+        /// 成员 Id
+        /// </summary>
         public ReadOnlyCollection<string> MemberIds {
             get {
                 return new ReadOnlyCollection<string>(ids.ToList());
             }
         }
 
+        /// <summary>
+        /// 静音成员 Id
+        /// </summary>
         public ReadOnlyCollection<string> MutedMemberIds {
             get {
                 return new ReadOnlyCollection<string>(mutedIds.ToList());
             }
         }
 
+        /// <summary>
+        /// 未读消息数量
+        /// </summary>
         public int Unread {
             get; internal set;
         }
 
+        /// <summary>
+        /// 最新的一条消息
+        /// </summary>
         public LCIMMessage LastMessage {
             get; internal set;
         }
 
+        /// <summary>
+        /// 创建时间
+        /// </summary>
         public DateTime CreatedAt {
             get; internal set;
         }
 
+        /// <summary>
+        /// 更新时间
+        /// </summary>
         public DateTime UpdatedAt {
             get; internal set;
         }
 
+        /// <summary>
+        /// 最新送达消息时间戳
+        /// </summary>
         public long LastDeliveredTimestamp {
             get; internal set;
         }
 
+        /// <summary>
+        /// 最新送达消息时间
+        /// </summary>
         public DateTime LastDeliveredAt {
             get {
                 DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(LastDeliveredTimestamp);
@@ -72,10 +113,16 @@ namespace LeanCloud.Realtime {
             }
         }
 
+        /// <summary>
+        /// 最新已读消息时间戳
+        /// </summary>
         public long LastReadTimestamp {
             get; internal set;
         }
 
+        /// <summary>
+        /// 最新已读消息时间
+        /// </summary>
         public DateTime LastReadAt {
             get {
                 DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(LastReadTimestamp);
@@ -83,6 +130,11 @@ namespace LeanCloud.Realtime {
             }
         }
 
+        /// <summary>
+        /// 设置/获取对话属性
+        /// </summary>
+        /// <param name="key"></param>
+        /// <returns></returns>
         public object this[string key] {
             get {
                 return customProperties[key];
@@ -92,6 +144,9 @@ namespace LeanCloud.Realtime {
             }
         }
 
+        /// <summary>
+        /// 是否已静音
+        /// </summary>
         public bool IsMute {
             get; private set;
         }
@@ -100,7 +155,7 @@ namespace LeanCloud.Realtime {
             get; private set;
         }
 
-        private Dictionary<string, object> customProperties;
+        private readonly Dictionary<string, object> customProperties;
 
         internal HashSet<string> ids;
 
@@ -128,7 +183,7 @@ namespace LeanCloud.Realtime {
             if (LastMessage == null) {
                 return;
             }
-            await Client.ConversationController.Read(Id, LastMessage);
+            await Client.MessageController.Read(Id, LastMessage);
         }
 
         /// <summary>
@@ -374,7 +429,7 @@ namespace LeanCloud.Realtime {
         /// <param name="limit">限制</param>
         /// <param name="messageType">消息类型</param>
         /// <returns></returns>
-        public async Task<List<LCIMMessage>> QueryMessages(LCIMMessageQueryEndpoint start = null,
+        public async Task<ReadOnlyCollection<LCIMMessage>> QueryMessages(LCIMMessageQueryEndpoint start = null,
             LCIMMessageQueryEndpoint end = null,
             LCIMMessageQueryDirection direction = LCIMMessageQueryDirection.NewToOld,
             int limit = 20,
diff --git a/Realtime/Internal/Connection/LCConnection.cs b/Realtime/Internal/Connection/LCConnection.cs
index 7204feb..ab98eba 100644
--- a/Realtime/Internal/Connection/LCConnection.cs
+++ b/Realtime/Internal/Connection/LCConnection.cs
@@ -34,16 +34,31 @@ namespace LeanCloud.Realtime.Internal.Connection {
         /// </summary>
         private const int HEART_BEAT_INTERVAL = 5000;
 
+        /// <summary>
+        /// 通知事件
+        /// </summary>
         internal Action<GenericCommand> OnNotification;
 
+        /// <summary>
+        /// 断线事件
+        /// </summary>
         internal Action OnDisconnect;
 
+        /// <summary>
+        /// 开始重连事件
+        /// </summary>
         internal Action OnReconnecting;
 
+        /// <summary>
+        /// 重连成功事件
+        /// </summary>
         internal Action OnReconnected;
 
         internal string id;
 
+        /// <summary>
+        /// 请求回调缓存
+        /// </summary>
         private readonly Dictionary<int, TaskCompletionSource<GenericCommand>> responses;
 
         private int requestI = 1;
@@ -61,7 +76,7 @@ namespace LeanCloud.Realtime.Internal.Connection {
             router = new LCRTMRouter();
             client = new LCWebSocketClient(router, heartBeat) {
                 OnMessage = OnClientMessage,
-                OnDisconnect = OnClientDisconnect
+                OnClose = OnClientDisconnect
             };
         }
 
@@ -69,41 +84,63 @@ namespace LeanCloud.Realtime.Internal.Connection {
             await client.Connect();
         }
 
+        /// <summary>
+        /// 重置连接
+        /// </summary>
+        /// <returns></returns>
         internal async Task Reset() {
-            router.Reset();
+            // 关闭就连接
             await client.Close();
+            // 重新创建连接组件
             heartBeat = new LCHeartBeat(this, HEART_BEAT_INTERVAL, HEART_BEAT_INTERVAL);
             router = new LCRTMRouter();
             client = new LCWebSocketClient(router, heartBeat) {
                 OnMessage = OnClientMessage,
-                OnDisconnect = OnClientDisconnect
+                OnClose = OnClientDisconnect
             };
             await Reconnect();
         }
 
+        /// <summary>
+        /// 发送请求，会在收到应答后返回
+        /// </summary>
+        /// <param name="request"></param>
+        /// <returns></returns>
         internal async Task<GenericCommand> SendRequest(GenericCommand request) {
             TaskCompletionSource<GenericCommand> tcs = new TaskCompletionSource<GenericCommand>();
             request.I = requestI++;
             responses.Add(request.I, tcs);
-            LCLogger.Debug($"{id} => {FormatCommand(request)}");
-            byte[] bytes = request.ToByteArray();
-            Task sendTask = client.Send(bytes);
-            if (await Task.WhenAny(sendTask, Task.Delay(SEND_TIMEOUT)) == sendTask) {
-                try {
-                    await sendTask;
-                } catch (Exception e) {
-                    tcs.TrySetException(e);
-                }
-            } else {
-                tcs.TrySetException(new TimeoutException("Send request"));
+            try {
+                await SendCommand(request);
+            } catch (Exception e) {
+                tcs.TrySetException(e);
             }
             return await tcs.Task;
         }
 
+        /// <summary>
+        /// 发送命令
+        /// </summary>
+        /// <param name="command"></param>
+        /// <returns></returns>
+        internal async Task SendCommand(GenericCommand command) {
+            LCLogger.Debug($"{id} => {FormatCommand(command)}");
+            byte[] bytes = command.ToByteArray();
+            Task sendTask = client.Send(bytes);
+            if (await Task.WhenAny(sendTask, Task.Delay(SEND_TIMEOUT)) == sendTask) {
+                await sendTask;
+            } else {
+                throw new TimeoutException("Send request");
+            }
+        }
+
+        /// <summary>
+        /// 关闭连接
+        /// </summary>
+        /// <returns></returns>
         internal async Task Close() {
             OnNotification = null;
             OnDisconnect = null;
-            heartBeat.Stop();
             await client.Close();
         }
 
@@ -154,8 +191,6 @@ namespace LeanCloud.Realtime.Internal.Connection {
                     try {
                         LCLogger.Debug($"Reconnecting... {reconnectCount}");
                         await client.Connect();
-                        client.OnMessage = OnClientMessage;
-                        client.OnDisconnect = OnClientDisconnect;
                         break;
                     } catch (Exception e) {
                         reconnectCount++;
@@ -167,11 +202,13 @@ namespace LeanCloud.Realtime.Internal.Connection {
                 if (reconnectCount < MAX_RECONNECT_TIMES) {
                     // 重连成功
                     LCLogger.Debug("Reconnected");
+                    client.OnMessage = OnClientMessage;
+                    client.OnClose = OnClientDisconnect;
                     OnReconnected?.Invoke();
                     break;
                 } else {
                     // 重置 Router，继续尝试重连
-                    router.Reset();
+                    router = new LCRTMRouter();
                 }
             }
         }
diff --git a/Realtime/Internal/Connection/LCHeartBeat.cs b/Realtime/Internal/Connection/LCHeartBeat.cs
index be26f5f..fa343d5 100644
--- a/Realtime/Internal/Connection/LCHeartBeat.cs
+++ b/Realtime/Internal/Connection/LCHeartBeat.cs
@@ -6,7 +6,7 @@ using LeanCloud.Realtime.Protocol;
 
 namespace LeanCloud.Realtime.Internal.Connection {
     /// <summary>
-    /// 心跳控制器
+    /// 心跳控制器，由于 .Net Standard 2.0 不支持发送 ping frame，所以需要发送逻辑心跳
     /// 1. 每次接收到消息后开始监听，如果在 pingInterval 时间内没有再次接收到消息，则发送 ping 请求；
     /// 2. 发送后等待 pongInterval 时间，如果在此时间内接收到了任何消息，则取消并重新开始监听 1；
     /// 3. 如果没收到消息，则认为超时并回调，连接层接收回调后放弃当前连接，以断线逻辑处理
diff --git a/Realtime/Internal/Controller/LCIMMessageController.cs b/Realtime/Internal/Controller/LCIMMessageController.cs
index d041b21..83deb91 100644
--- a/Realtime/Internal/Controller/LCIMMessageController.cs
+++ b/Realtime/Internal/Controller/LCIMMessageController.cs
@@ -223,6 +223,7 @@ namespace LeanCloud.Realtime.Internal.Controller {
             message.IsTransient = direct.Transient;
             // 通知服务端已接收
             if (!message.IsTransient) {
+                // 只有非暂态消息才需要发送 ack
                 _ = Ack(message.ConversationId, message.Id);
             }
             // 获取对话
diff --git a/Realtime/Internal/Controller/LCIMSessionController.cs b/Realtime/Internal/Controller/LCIMSessionController.cs
index 894502e..336dbb9 100644
--- a/Realtime/Internal/Controller/LCIMSessionController.cs
+++ b/Realtime/Internal/Controller/LCIMSessionController.cs
@@ -18,9 +18,9 @@ namespace LeanCloud.Realtime.Internal.Controller {
         /// 打开会话
         /// </summary>
         /// <returns></returns>
-        internal async Task Open(bool reconnect) {
+        internal async Task Open(bool force) {
             SessionCommand session = NewSessionCommand();
-            session.R = reconnect;
+            session.R = !force;
             GenericCommand request = NewCommand(CommandType.Session, OpType.Open);
             request.SessionMessage = session;
             GenericCommand response = await Client.Connection.SendRequest(request);
@@ -78,7 +78,9 @@ namespace LeanCloud.Realtime.Internal.Controller {
             SessionCommand session = new SessionCommand();
             if (Client.Tag != null) {
                 session.Tag = Client.Tag;
-                session.DeviceId = Guid.NewGuid().ToString();
+            }
+            if (Client.DeviceId != null) {
+                session.DeviceId = Client.DeviceId;
             }
             if (Client.SignatureFactory != null) {
                 LCIMSignature signature = Client.SignatureFactory.CreateConnectSignature(Client.Id);
diff --git a/Realtime/Internal/Router/LCRTMRouter.cs b/Realtime/Internal/Router/LCRTMRouter.cs
index ad7d9f5..d663b46 100644
--- a/Realtime/Internal/Router/LCRTMRouter.cs
+++ b/Realtime/Internal/Router/LCRTMRouter.cs
@@ -28,13 +28,6 @@ namespace LeanCloud.Realtime.Internal.Router {
             return rtmServer;
         }
 
-        /// <summary>
-        /// 重置服务器地址缓存
-        /// </summary>
-        internal void Reset() {
-            rtmServer = null;
-        }
-
         async Task<LCRTMServer> Fetch() {
             string server = await LCApplication.AppRouter.GetRealtimeServer();
             string url = $"{server}/v1/route?appId={LCApplication.AppId}&secure=1";
diff --git a/Realtime/Internal/WebSocket/LCWebSocketClient.cs b/Realtime/Internal/WebSocket/LCWebSocketClient.cs
index 5d80ccc..75af743 100644
--- a/Realtime/Internal/WebSocket/LCWebSocketClient.cs
+++ b/Realtime/Internal/WebSocket/LCWebSocketClient.cs
@@ -7,21 +7,31 @@ using LeanCloud.Realtime.Internal.Connection;
 
 namespace LeanCloud.Realtime.Internal.WebSocket {
     /// <summary>
-    /// WebSocket 客户端，只与通信协议相关
+    /// WebSocket 客户端，负责底层连接和事件，只与通信协议相关
     /// </summary>
     internal class LCWebSocketClient {
         // .net standard 2.0 好像在拼合 Frame 时有 bug，所以将这个值调整大一些
         private const int RECV_BUFFER_SIZE = 1024 * 5;
 
+        /// <summary>
+        /// 关闭超时
+        /// </summary>
         private const int CLOSE_TIMEOUT = 5000;
 
+        /// <summary>
+        /// 连接超时
+        /// </summary>
         private const int CONNECT_TIMEOUT = 10000;
 
+        /// <summary>
+        /// 消息事件
+        /// </summary>
         internal Action<byte[]> OnMessage;
 
-        internal Action OnDisconnect;
-
-        internal Action OnReconnect;
+        /// <summary>
+        /// 连接关闭
+        /// </summary>
+        internal Action OnClose;
 
         private ClientWebSocket ws;
 
@@ -34,6 +44,10 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             this.heartBeat = heartBeat;
         }
 
+        /// <summary>
+        /// 连接
+        /// </summary>
+        /// <returns></returns>
         internal async Task Connect() {
             try {
                 LCRTMServer rtmServer = await router.GetServer();
@@ -53,6 +67,11 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             _ = StartReceive();
         }
 
+        /// <summary>
+        /// 连接指定 ws 服务器
+        /// </summary>
+        /// <param name="server"></param>
+        /// <returns></returns>
         private async Task Connect(string server) {
             LCLogger.Debug($"Connecting WebSocket: {server}");
             Task timeoutTask = Task.Delay(CONNECT_TIMEOUT);
@@ -66,11 +85,14 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             }
         }
 
+        /// <summary>
+        /// 主动关闭连接
+        /// </summary>
+        /// <returns></returns>
         internal async Task Close() {
             LCLogger.Debug("Closing WebSocket");
             OnMessage = null;
-            OnDisconnect = null;
-            OnReconnect = null;
+            OnClose = null;
             heartBeat.Stop();
             try {
                 // 发送关闭帧可能会很久，所以增加超时
@@ -87,6 +109,11 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             }
         }
 
+        /// <summary>
+        /// 发送数据
+        /// </summary>
+        /// <param name="data"></param>
+        /// <returns></returns>
         internal async Task Send(byte[] data) {
             ArraySegment<byte> bytes = new ArraySegment<byte>(data);
             if (ws.State == WebSocketState.Open) {
@@ -103,28 +130,30 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             }
         }
 
+        /// <summary>
+        /// 接收数据
+        /// </summary>
+        /// <returns></returns>
         private async Task StartReceive() {
             byte[] buffer = new byte[RECV_BUFFER_SIZE];
             try {
                 while (ws.State == WebSocketState.Open) {
                     WebSocketReceiveResult result = await ws.ReceiveAsync(new ArraySegment<byte>(buffer), default);
                     if (result.MessageType == WebSocketMessageType.Close) {
-                        // 由服务端发起关闭
                         LCLogger.Debug($"Receive Closed: {result.CloseStatus}");
-                        LCLogger.Debug($"ws state: {ws.State}");
-                        // 这里有可能是客户端主动关闭，也有可能是服务端主动关闭
                         if (ws.State == WebSocketState.CloseReceived) {
                             // 如果是服务端主动关闭，则挥手关闭，并认为是断线
                             try {
-                                await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, string.Empty, default);
+                                Task closeTask = ws.CloseAsync(WebSocketCloseStatus.NormalClosure, string.Empty, default);
+                                await Task.WhenAny(closeTask, Task.Delay(CLOSE_TIMEOUT));
                             } catch (Exception e) {
                                 LCLogger.Error(e);
                             } finally {
-                                OnDisconnect?.Invoke();
+                                HandleExceptionClose();
                             }
                         }
                     } else if (result.MessageType == WebSocketMessageType.Binary) {
-                        _ = heartBeat.Update(HandleClose);
+                        _ = heartBeat.Update(HandleExceptionClose);
                         // 拼合 WebSocket Message
                         int length = result.Count;
                         byte[] data = new byte[length];
@@ -137,17 +166,19 @@ namespace LeanCloud.Realtime.Internal.WebSocket {
             } catch (Exception e) {
                 // 客户端网络异常
                 LCLogger.Error(e);
-                OnDisconnect?.Invoke();
+                OnClose?.Invoke();
             }
         }
 
-        private void HandleClose() {
+        private void HandleExceptionClose() {
             try {
                 heartBeat.Stop();
                 ws.Abort();
                 ws.Dispose();
             } catch (Exception e) {
                 LCLogger.Error(e);
+            } finally {
+                OnClose?.Invoke();
             }
         }
     }
diff --git a/Realtime/LCIMClient.cs b/Realtime/LCIMClient.cs
index ded9bce..be282b3 100644
--- a/Realtime/LCIMClient.cs
+++ b/Realtime/LCIMClient.cs
@@ -23,8 +23,39 @@ namespace LeanCloud.Realtime {
             get; private set;
         }
 
+        public string DeviceId {
+            get; private set;
+        }
+
         #region 事件
 
+        #region 连接状态事件
+
+        /// <summary>
+        /// 客户端连接断开
+        /// </summary>
+        public Action OnPaused {
+            get; set;
+        }
+
+        /// <summary>
+        /// 客户端连接恢复正常
+        /// </summary>
+        public Action OnResume {
+            get; set;
+        }
+
+        /// <summary>
+        /// 当前客户端被服务端强行下线
+        /// </summary>
+        public Action<int, string> OnClose {
+            get; set;
+        }
+
+        #endregion
+
+        #region 对话事件
+
         /// <summary>
         /// 当前用户被加入某个对话的黑名单
         /// </summary>
@@ -49,55 +80,6 @@ namespace LeanCloud.Realtime {
         /// </summary>
         public Action<LCIMConversation, string> OnUnmuted;
 
-        /// <summary>
-        /// 客户端连接断开
-        /// </summary>
-        public Action OnPaused {
-            get; set;
-        }
-
-        /// <summary>
-        /// 客户端连接恢复正常
-        /// </summary>
-        public Action OnResume {
-            get; set;
-        }
-
-        /// <summary>
-        /// 当前客户端被服务端强行下线
-        /// </summary>
-        public Action<int, string> OnClose {
-            get; set;
-        }
-
-        /// <summary>
-        /// 客户端连接断开
-        /// </summary>
-        public Action OnDisconnect {
-            get; set;
-        }
-
-        /// <summary>
-        /// 客户端正在重连
-        /// </summary>
-        public Action OnReconnecting {
-            get; set;
-        }
-
-        /// <summary>
-        /// 客户端重连成功
-        /// </summary>
-        public Action OnReconnected {
-            get; set;
-        }
-
-        /// <summary>
-        /// 用户在其他客户端登录，当前客户端被服务端强行下线
-        /// </summary>
-        public Action<string> OnConflict {
-            get; set;
-        }
-
         /// <summary>
         /// 该对话信息被更新
         /// </summary>
@@ -164,6 +146,10 @@ namespace LeanCloud.Realtime {
         /// </summary>
         public Action<LCIMConversation, string, string, string> OnMemberInfoUpdated;
 
+        #endregion
+
+        #region 消息事件
+
         /// <summary>
         /// 当前用户收到消息
         /// </summary>
@@ -207,18 +193,23 @@ namespace LeanCloud.Realtime {
         }
 
         /// <summary>
-        /// 
+        /// 最近分发消息更新
         /// </summary>
         public Action OnLastDeliveredAtUpdated {
             get; set;
         }
 
+        /// <summary>
+        /// 最近已读消息更新
+        /// </summary>
         public Action OnLastReadAtUpdated {
             get; set;
         }
 
         #endregion
 
+        #endregion
+
         internal ILCIMSignatureFactory SignatureFactory {
             get; private set;
         }
@@ -255,9 +246,11 @@ namespace LeanCloud.Realtime {
 
         public LCIMClient(string clientId,
             string tag = null,
+            string deviceId = null,
             ILCIMSignatureFactory signatureFactory = null) {
             Id = clientId;
             Tag = tag;
+            DeviceId = deviceId;
             SignatureFactory = signatureFactory;
 
             ConversationDict = new Dictionary<string, LCIMConversation>();
@@ -278,13 +271,14 @@ namespace LeanCloud.Realtime {
         }
 
         /// <summary>
-        /// 连接
+        /// 登录
         /// </summary>
+        /// <param name="force">是否强制登录</param>
         /// <returns></returns>
-        public async Task Open(bool reconnect = false) {
+        public async Task Open(bool force = true) {
             await Connection.Connect();
             // 打开 Session
-            await SessionController.Open(reconnect);
+            await SessionController.Open(force);
         }
 
         /// <summary>
@@ -442,7 +436,7 @@ namespace LeanCloud.Realtime {
         }
 
         private void OnConnectionDisconnect() {
-            OnDisconnect?.Invoke();
+            OnPaused?.Invoke();
         }
 
         private void OnConnectionReconnect() {
@@ -454,7 +448,7 @@ namespace LeanCloud.Realtime {
                 // 打开 Session
                 await SessionController.Reopen();
                 // 回调用户
-                OnReconnected?.Invoke();
+                OnResume?.Invoke();
             } catch (Exception e) {
                 LCLogger.Error(e);
                 await Connection.Close();
diff --git a/Realtime/Message/LCIMMessage.cs b/Realtime/Message/LCIMMessage.cs
index 2c6e70a..786c229 100644
--- a/Realtime/Message/LCIMMessage.cs
+++ b/Realtime/Message/LCIMMessage.cs
@@ -78,6 +78,10 @@ namespace LeanCloud.Realtime {
             get; internal set;
         }
 
+        public bool IsTransient {
+            get; internal set;
+        }
+
         internal LCIMMessage() {
         }
     }