clean up code

example/lib/page/temp.dart

@@ -1,4 +0,0 @@
-import 'package:flutter/material.dart';
-
-void t(){
-}

lib/src/widget/controller_widget_builder.dart

@@ -1,5 +1,4 @@
 import 'dart:async';
-import 'dart:io';
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';