1、清除白板数据时不走异步锁

lib/components/white_board/white_board.dart

@@ -172,16 +172,15 @@ class _FWhiteBoardState extends State<FWhiteBoard> {
       _asyncDrawQueue.add(jsonData);
       return;
     }
-    _asyncDrawLock = true;
-
     var data = jsonDecode(jsonData);
 
     /// 清除时走的逻辑
     if (data["isClear"] == "true") {
       _clearUserLines(data["u_Id"]);
-      _asyncDrawLock = false;
       return;
     }
+    _asyncDrawLock = true;
+
     List<dynamic> pointsList = PointsUtil.decompressPointsList(data["points"]);
     Line line = Line(
       color: Color(int.parse(data["color"])),