diff --git a/Common/AppRouter/AppRouter.cs b/Common/AppRouter/LCAppRouter.cs
similarity index 69%
rename from Common/AppRouter/AppRouter.cs
rename to Common/AppRouter/LCAppRouter.cs
index a46ed81..523b465 100644
--- a/Common/AppRouter/AppRouter.cs
+++ b/Common/AppRouter/LCAppRouter.cs
@@ -5,14 +5,14 @@ using System.Collections.Generic;
 using Newtonsoft.Json;
 
 namespace LeanCloud.Common {
-    public class AppRouter {
+    public class LCAppRouter {
         private readonly string appId;
 
         private readonly string server;
 
-        private AppServer appServer;
+        private LCAppServer appServer;
 
-        public AppRouter(string appId, string server) {
+        public LCAppRouter(string appId, string server) {
             if (!IsInternalApp(appId) && string.IsNullOrEmpty(server)) {
                 // 国内节点必须配置自定义域名
                 throw new Exception("Please init with your server url.");
@@ -26,36 +26,49 @@ namespace LeanCloud.Common {
             if (!string.IsNullOrEmpty(server)) {
                 return server;
             }
+            LCAppServer appServ = await FetchAppServer();
+            return appServ.ApiServer;
+        }
+
+        public async Task<string> GetRealtimeServer() {
+            if (!string.IsNullOrEmpty(server)) {
+                return server;
+            }
+            LCAppServer appServ = await FetchAppServer();
+            return appServ.PushServer;
+        }
+
+        async Task<LCAppServer> FetchAppServer() {
             // 判断节点地区
             if (!IsInternalApp(appId)) {
                 // 国内节点必须配置自定义域名
                 throw new Exception("Please init with your server url.");
             }
             // 向 App Router 请求地址
-            if (appServer == null || appServer.IsExpired) {
+            if (appServer == null || !appServer.IsValid) {
                 try {
                     HttpRequestMessage request = new HttpRequestMessage {
                         RequestUri = new Uri($"https://app-router.com/2/route?appId={appId}"),
                         Method = HttpMethod.Get
                     };
                     HttpClient client = new HttpClient();
-                    HttpUtils.PrintRequest(client, request);
+                    LCHttpUtils.PrintRequest(client, request);
                     HttpResponseMessage response = await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
                     request.Dispose();
 
                     string resultString = await response.Content.ReadAsStringAsync();
                     response.Dispose();
-                    HttpUtils.PrintResponse(response, resultString);
+                    LCHttpUtils.PrintResponse(response, resultString);
 
                     Dictionary<string, object> data = JsonConvert.DeserializeObject<Dictionary<string, object>>(resultString);
-                    appServer = new AppServer(data);
+                    appServer = new LCAppServer(data);
                 } catch (Exception e) {
-                    Logger.Error(e.Message);
+                    LCLogger.Error(e.Message);
                     // 拉取服务地址失败后，使用国际节点的默认服务地址
-                    appServer = AppServer.GetInternalFallbackAppServer(appId);
+                    appServer = LCAppServer.GetInternalFallbackAppServer(appId);
                 }
             }
-            return appServer.ApiServer;
+            return appServer;
         }
 
         private static bool IsInternalApp(string appId) {
diff --git a/Common/AppRouter/AppServer.cs b/Common/AppRouter/LCAppServer.cs
similarity index 80%
rename from Common/AppRouter/AppServer.cs
rename to Common/AppRouter/LCAppServer.cs
index 0ae29ae..7f4e3ec 100644
--- a/Common/AppRouter/AppServer.cs
+++ b/Common/AppRouter/LCAppServer.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 
 namespace LeanCloud.Common {
-    public class AppServer {
+    public class LCAppServer {
         public string ApiServer {
             get; private set;
         }
@@ -19,9 +19,9 @@ namespace LeanCloud.Common {
             get; private set;
         }
 
-        public bool IsExpired {
+        public bool IsValid {
             get {
-                return ttl != -1 && DateTime.Now > expiredAt;
+                return ttl != -1 || DateTime.Now < expiredAt;
             }
         }
 
@@ -29,7 +29,7 @@ namespace LeanCloud.Common {
 
         private readonly int ttl;
 
-        public AppServer(Dictionary<string, object> data) {
+        public LCAppServer(Dictionary<string, object> data) {
             ApiServer = GetUrlWithScheme(data["api_server"] as string);
             PushServer = GetUrlWithScheme(data["push_server"] as string);
             EngineServer = GetUrlWithScheme(data["engine_server"] as string);
@@ -41,9 +41,9 @@ namespace LeanCloud.Common {
             return url.StartsWith("https://") ? url : $"https://{url}";
         }
 
-        internal static AppServer GetInternalFallbackAppServer(string appId) {
+        internal static LCAppServer GetInternalFallbackAppServer(string appId) {
             string prefix = appId.Substring(0, 8).ToLower();
-            return new AppServer(new Dictionary<string, object> {
+            return new LCAppServer(new Dictionary<string, object> {
                 { "api_server", $"https://{prefix}.api.lncldglobal.com" },
                 { "push_server", $"https://{prefix}.engine.lncldglobal.com" },
                 { "engine_server", $"https://{prefix}.push.lncldglobal.com" },
diff --git a/Common/Http/HttpUtils.cs b/Common/Http/LCHttpUtils.cs
similarity index 93%
rename from Common/Http/HttpUtils.cs
rename to Common/Http/LCHttpUtils.cs
index 7edaa6e..40fd13f 100644
--- a/Common/Http/HttpUtils.cs
+++ b/Common/Http/LCHttpUtils.cs
@@ -3,7 +3,7 @@ using System.Text;
 using System.Net.Http;
 
 namespace LeanCloud.Common {
-    public static class HttpUtils {
+    public static class LCHttpUtils {
         public static void PrintRequest(HttpClient client, HttpRequestMessage request, string content = null) {
             if (client == null) {
                 return;
@@ -31,7 +31,7 @@ namespace LeanCloud.Common {
                 sb.AppendLine($"Content: {content}");
             }
             sb.AppendLine("=== HTTP Request End ===");
-            Logger.Debug(sb.ToString());
+            LCLogger.Debug(sb.ToString());
         }
 
         public static void PrintResponse(HttpResponseMessage response, string content = null) {
@@ -43,7 +43,7 @@ namespace LeanCloud.Common {
                 sb.AppendLine($"Content: {content}");
             }
             sb.AppendLine("=== HTTP Response End ===");
-            Logger.Debug(sb.ToString());
+            LCLogger.Debug(sb.ToString());
         }
     }
 }
diff --git a/Common/Json/JsonExtensions.cs b/Common/Json/LCJsonUtils.cs
similarity index 96%
rename from Common/Json/JsonExtensions.cs
rename to Common/Json/LCJsonUtils.cs
index d0a131b..25ec9fd 100644
--- a/Common/Json/JsonExtensions.cs
+++ b/Common/Json/LCJsonUtils.cs
@@ -5,7 +5,7 @@ namespace LeanCloud.Common {
     /// <summary>
     /// 为 Json 解析提供异步接口
     /// </summary>
-    public static class JsonUtils {
+    public static class LCJsonUtils {
         public static async Task<string> SerializeObjectAsync(object obj) {
             string str = null;
             await Task.Run(() => {
diff --git a/Common/Log/LogLevel.cs b/Common/Log/LCLogLevel.cs
similarity index 92%
rename from Common/Log/LogLevel.cs
rename to Common/Log/LCLogLevel.cs
index 5d9344c..fefcd9d 100644
--- a/Common/Log/LogLevel.cs
+++ b/Common/Log/LCLogLevel.cs
@@ -2,7 +2,7 @@
     /// <summary>
     /// 日志级别
     /// </summary>
-    public enum LogLevel {
+    public enum LCLogLevel {
         /// <summary>
         /// 调试级别
         /// </summary>
diff --git a/Common/Log/Logger.cs b/Common/Log/LCLogger.cs
similarity index 58%
rename from Common/Log/Logger.cs
rename to Common/Log/LCLogger.cs
index 4e499d5..63b917e 100644
--- a/Common/Log/Logger.cs
+++ b/Common/Log/LCLogger.cs
@@ -4,37 +4,37 @@ namespace LeanCloud.Common {
     /// <summary>
     /// 日志类
     /// </summary>
-    public static class Logger {
+    public static class LCLogger {
         /// <summary>
         /// 日志回调接口，方便开发者调试
         /// </summary>
         /// <value>The log delegate.</value>
-        public static Action<LogLevel, string> LogDelegate {
+        public static Action<LCLogLevel, string> LogDelegate {
             get; set;
         }
 
         public static void Debug(string log) {
-            LogDelegate?.Invoke(LogLevel.Debug, log);
+            LogDelegate?.Invoke(LCLogLevel.Debug, log);
         }
 
         public static void Debug(string format, params object[] args) {
-            LogDelegate?.Invoke(LogLevel.Debug, string.Format(format, args));
+            LogDelegate?.Invoke(LCLogLevel.Debug, string.Format(format, args));
         }
 
         public static void Warn(string log) {
-            LogDelegate?.Invoke(LogLevel.Warn, log);
+            LogDelegate?.Invoke(LCLogLevel.Warn, log);
         }
 
         public static void Warn(string format, params object[] args) {
-            LogDelegate?.Invoke(LogLevel.Warn, string.Format(format, args));
+            LogDelegate?.Invoke(LCLogLevel.Warn, string.Format(format, args));
         }
 
         public static void Error(string log) {
-            LogDelegate?.Invoke(LogLevel.Error, log);
+            LogDelegate?.Invoke(LCLogLevel.Error, log);
         }
 
         public static void Error(string format, params object[] args) {
-            LogDelegate?.Invoke(LogLevel.Error, string.Format(format, args));
+            LogDelegate?.Invoke(LCLogLevel.Error, string.Format(format, args));
         }
     }
 }
diff --git a/Common/Task/TaskExtensions.cs b/Common/Task/LCTaskExtensions.cs
similarity index 99%
rename from Common/Task/TaskExtensions.cs
rename to Common/Task/LCTaskExtensions.cs
index 2137ec5..bd0b0cb 100644
--- a/Common/Task/TaskExtensions.cs
+++ b/Common/Task/LCTaskExtensions.cs
@@ -10,7 +10,7 @@ namespace LeanCloud.Common {
     /// <summary>
     /// Provides helper methods that allow us to use terser code elsewhere.
     /// </summary>
-    public static class TaskExtensions {
+    public static class LCTaskExtensions {
         /// <summary>
         /// Ensures a task (even null) is awaitable.
         /// </summary>