Merged enix's fix (THX enix) and made a little change (because close method dose not work).

websocket-sharp.userprefs

@@ -1,8 +1,8 @@
 <Properties>
-  <MonoDevelop.Ide.Workspace ActiveConfiguration="Release_Ubuntu" ctype="Workspace" />
+  <MonoDevelop.Ide.Workspace ActiveConfiguration="Release" ctype="Workspace" />
   <MonoDevelop.Ide.Workbench ActiveDocument="websocket-sharp/WebSocket.cs" ctype="Workbench">
     <Files>
-      <File FileName="websocket-sharp/WebSocket.cs" Line="282" Column="1" />
+      <File FileName="websocket-sharp/WebSocket.cs" Line="80" Column="19" />
     </Files>
   </MonoDevelop.Ide.Workbench>
   <MonoDevelop.Ide.DebuggingService.Breakpoints>

websocket-sharp/WebSocket.cs

@@ -53,6 +53,8 @@ namespace WebSocketSharp
       get { return uri.ToString(); }
     }
 
+    private Object sync = new Object();
+
     private volatile WsState readyState;
     public WsState ReadyState
     {
@@ -63,17 +65,18 @@ namespace WebSocketSharp
         switch (value)
         {
           case WsState.OPEN:
+            readyState = value;
             if (OnOpen != null)
             {
               OnOpen(this, EventArgs.Empty);
             }
-            goto default;
+            break;
           case WsState.CLOSING:
           case WsState.CLOSED:
+            lock(sync)
+            {
               close(value);
-            break;
-          default:
-            readyState = value;
+            }
             break;
         }
       }

wsclient/wsclient.cs

@@ -14,11 +14,11 @@ namespace Example
       //using (WebSocket ws = new WebSocket("ws://localhost:8000/"))
       using (WebSocket ws = new WebSocket("ws://localhost:8000/", "chat"))
       {
-        /*ws.OnOpen += (o, e) =>
+        ws.OnOpen += (o, e) =>
         {
-          //Do something.
+          ws.Send("Hi, all!");
         };
-         */
+
         ws.OnMessage += (o, s) =>
         {
 #if NOTIFY