From 34a6b91bf69b706b41f43e529a8b1803118ed73f Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Tue, 11 Oct 2016 15:38:28 +0900
Subject: [PATCH] [Modify] Polish it

---
 websocket-sharp/Server/WebSocketServer.cs | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/websocket-sharp/Server/WebSocketServer.cs b/websocket-sharp/Server/WebSocketServer.cs
index 49cc8491..17783453 100644
--- a/websocket-sharp/Server/WebSocketServer.cs
+++ b/websocket-sharp/Server/WebSocketServer.cs
@@ -402,13 +402,20 @@ namespace WebSocketSharp.Server
       }
 
       set {
-        var msg = _state.CheckIfAvailable (true, false, false);
-        if (msg != null) {
+        string msg;
+        if (!checkIfAvailable (true, false, false, true, out msg)) {
           _logger.Error (msg);
           return;
         }
 
-        _services.KeepClean = value;
+        lock (_sync) {
+          if (!checkIfAvailable (true, false, false, true, out msg)) {
+            _logger.Error (msg);
+            return;
+          }
+
+          _services.KeepClean = value;
+        }
       }
     }