From 9a2dc74cbc024439dcc8d508be7a1e0348a6ad67 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Fri, 18 Aug 2017 14:27:13 +0900
Subject: [PATCH] [Modify] Throw exception

---
 websocket-sharp/Server/WebSocketSessionManager.cs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index 476a77ed..f87d3a0d 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -962,8 +962,12 @@ namespace WebSocketSharp.Server
     public void CloseSession (string id, CloseStatusCode code, string reason)
     {
       IWebSocketSession session;
-      if (TryGetSession (id, out session))
-        session.Context.WebSocket.Close (code, reason);
+      if (!TryGetSession (id, out session)) {
+        var msg = "The session could not be found.";
+        throw new ArgumentException (msg, "id");
+      }
+
+      session.Context.WebSocket.Close (code, reason);
     }
 
     /// <summary>