[Modify] Throw exceptions

websocket-sharp/WebSocket.cs

@@ -2883,14 +2883,42 @@ namespace WebSocketSharp
     /// </param>
     public void CloseAsync (ushort code, string reason)
     {
-      string msg;
-      if (!CheckParametersForClose (code, reason, _client, out msg)) {
-        _logger.Error (msg);
-        error ("An error has occurred in closing the connection.", null);
+      if (!code.IsCloseStatusCode ()) {
+        var msg = "Less than 1000 or greater than 4999.";
+        throw new ArgumentOutOfRangeException ("code", msg);
+      }
+
+      if (_client && code == 1011) {
+        var msg = "1011 cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
+
+      if (!_client && code == 1010) {
+        var msg = "1010 cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
 
+      if (reason.IsNullOrEmpty ()) {
+        closeAsync (code, String.Empty);
         return;
       }
 
+      if (code == 1005) {
+        var msg = "1005 cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
+
+      byte[] bytes;
+      if (!reason.TryGetUTF8EncodedBytes (out bytes)) {
+        var msg = "It could not be UTF-8-encoded.";
+        throw new ArgumentException (msg, "reason");
+      }
+
+      if (bytes.Length > 123) {
+        var msg = "Its size is greater than 123 bytes.";
+        throw new ArgumentOutOfRangeException ("reason", msg);
+      }
+
       closeAsync (code, reason);
     }