重构NetManager支持MessagePair，新增TSRPCWsClient。

client/assets/scripts/Framework/Net/NetEvent.ts

@@ -2,24 +2,27 @@
  * 网络事件定义
  */
 export enum NetEvent {
+    /** 正在连接 */
+    Connecting = "net_connecting",
+
     /** 连接成功 */
     Connected = "net_connected",
-    
+
     /** 连接断开 */
     Disconnected = "net_disconnected",
-    
+
     /** 正在重连 */
     Reconnecting = "net_reconnecting",
-    
+
     /** 重连成功 */
     ReconnectSuccess = "net_reconnect_success",
-    
+
     /** 重连失败 */
     ReconnectFailed = "net_reconnect_failed",
-    
+
     /** 网络错误 */
     Error = "net_error",
-    
+
     /** 连接超时 */
     Timeout = "net_timeout"
 }