msg auto to empty string

example/.flutter-plugins-dependencies

-{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}],"android":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}],"macos":[],"linux":[],"windows":[],"web":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}]},"dependencyGraph":[{"name":"fluttertoast","dependencies":[]}],"date_created":"2020-07-05 14:58:23.372220","version":"1.19.0-4.3.pre"}
\ No newline at end of file
+{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}],"android":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}],"macos":[],"linux":[],"windows":[],"web":[{"name":"fluttertoast","path":"C:\\\\Users\\\\ponna\\\\Desktop\\\\my\\\\plugins\\\\fluttertoast\\\\","dependencies":[]}]},"dependencyGraph":[{"name":"fluttertoast","dependencies":[]}],"date_created":"2020-07-05 15:32:05.671138","version":"1.19.0-4.3.pre"}
\ No newline at end of file

example/pubspec.lock

@@ -71,7 +71,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "5.0.0"
+    version: "5.0.1"
   matcher:
     dependency: transitive
     description:

lib/fluttertoast.dart

@@ -51,7 +51,7 @@ class FlutterToast {
       textColor = Colors.white;
     }
     final Map<String, dynamic> params = <String, dynamic>{
-      'msg': msg,
+      'msg': msg ?? "",
       'length': toast,
       'time': timeInSecForIosWeb,
       'gravity': gravityToast,