Avoiding IO completion callback during the closing

net/base/test_completion_callback.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_BASE_TEST_COMPLETION_CALLBACK_H_
 #define NET_BASE_TEST_COMPLETION_CALLBACK_H_
 
 #include "base/message_loop.h"
 #include "net/base/completion_callback.h"
 
@@ skipping 20 matching lines @@
     DCHECK(!waiting_for_result_);
     while (!have_result_) {
       waiting_for_result_ = true;
       MessageLoop::current()->Run();
       waiting_for_result_ = false;
     }
     have_result_ = false;  // auto-reset for next callback
     return result_;
   }
 
+  bool have_result() const { return have_result_; }
+
  private:
   virtual void RunWithParams(const Tuple1<int>& params) {
     result_ = params.a;
     have_result_ = true;
     if (waiting_for_result_)
       MessageLoop::current()->Quit();
   }
 
   int result_;
   bool have_result_;
   bool waiting_for_result_;
 };
 
 #endif  // NET_BASE_TEST_COMPLETION_CALLBACK_H_