assert false when quiting

Recently, I had a trouble when using Ice3.4.2. Sometimes, an Ice assert is raised in ConnectionI.h #245 when my application is quiting.
It happens occasionally, so it puzzles me very much. By the way, only timeout proxy has the problem.

I have tried to analyze this problem by reviewing the source code of Ice3.4.2. And I guess that it is a bug in Ice3.4.2.
In ConnectionI::dispatch(ConnectionI.h #1442), the following code is added in Ice3.4.2.


//
// Decrease dispatch count.

//
if(!sentCBs.empty() || outAsync)

{

IceUtil::Monitor<IceUtil::Mutex>::Lock sync(*this);

if(--_dispatchCount == 0)

{

if(_state == StateClosing)

{

try

{

initiateShutdown();

}

catch(const LocalException& ex)

{

setState(StateClosed, ex);

}

}

else if(_state == StateFinished)

{

_reaper->add(this);

}

notifyAll();

}

}

Ice Assert is raised in initiateShutdown function. When a SocketOperationRead is retrieved from IOCP, first,
_readTimeout timer task is removed from the Timer through unscheduleTimeout(current.operation).
however _writeTimeout timer task still remains in it. Meanwhile, the application is quiting,
initiateShutdown is called and the program is trying to push _writeTimeout timer task into the Timer again,

bool inserted = _tasks.insert(make_pair(task, time)).second;

if(!inserted)

{

throw IllegalArgumentException(__FILE__, __LINE__, "task is already schedulded");

}

so the failure of the insert triggers an exception and then an assert is fired.

I have tried some ways to resolve it but no help, so how can I avoid this problem? and is it a bug in Ice3.4.2?

Thanks.