どうなってるんだろう。
実験：
#pre||>
    public void sessionClosed(IoSession session) throws Exception
    {
        System.out.println("SessionClosed()...");
        System.out.println("isClosing() = " + session.isClosing());
        System.out.println("isConnected() = " + session.isConnected());
    }
||<
結果：
 10828 [AnonymousIoService-6] INFO  xxxxyyyyHandler  - [/127.0.0.1:3643] CLOSED
 SessionClosed()...
 isClosing() = true
 isConnected() = false