method should decorate by tornado.web.asynchronous ?

[jacklee2012]

the project example code show blow:

def post(self):

        def _finish(num):
            print 'sended %d message(s)' % num
            self.render("index.html")

        message = EmailMessage(
            self.get_argument('subject'),
            self.get_argument('message'),
            '<your google mail>',
            [self.get_argument('email')],
            connection=self.mail_connection
        )
        message.send()#callback=_finish)
        self.render("index.html")

but if don't use tornado.web.asynchronous to decorate the post method, the socket will closed after the post method return
and cause:

Exception in callback <tornado.stack_context._StackContextWrapper object at 0x8cf2784>
    Traceback (most recent call last):
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/ioloop.py", line 399, in _run_callback
        callback()
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/iostream.py", line 304, in wrapper
        callback(*args)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/stack_context.py", line 199, in wrapped
        callback(*args, **kwargs)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 357, in inner
        self.set_result(key, result)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 291, in set_result
        self.run()
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 321, in run
        yielded = self.gen.send(next)
      File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 385, in docmd
        self.getreply(callback)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 107, in wrapper
        runner.run()
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 319, in run
        yielded = self.gen.throw(*exc_info)
      File "/usr/local/lib/python2.7/dist-packages/tornadomail/smtplib.py", line 356, in getreply
        line = yield gen.Task(self.sock.read_until, '\n')
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 341, in run
        self.yield_point.start(self)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/gen.py", line 223, in start
        self.func(*self.args, **self.kwargs)
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/iostream.py", line 160, in read_until
        self._check_closed()
      File "/usr/local/lib/python2.7/dist-packages/tornado-2.2-py2.7.egg/tornado/iostream.py", line 535, in _check_closed
        raise IOError("Stream is closed")
    IOError: Stream is closed