websocket close error

gistfile1.txt

2011-10-26_23:58:30.12356 [E 111026 23:58:30 periodic:46] Error in periodic callback
2011-10-26_23:58:30.12359     Traceback (most recent call last):
2011-10-26_23:58:30.12360       File "/home/ubuntu/test/libs/tornadio/tornadio/periodic.py", line 42, in _run
2011-10-26_23:58:30.12361         next_call = self.callback()
2011-10-26_23:58:30.12361       File "/home/ubuntu/test/libs/tornadio/tornadio/conn.py", line 141, in _heartbeat
2011-10-26_23:58:30.12362         self.close()
2011-10-26_23:58:30.12363       File "/home/ubuntu/test/libs/tornadio/tornadio/conn.py", line 85, in close
2011-10-26_23:58:30.12363         self._protocol.close()
2011-10-26_23:58:30.12364       File "/home/ubuntu/test/libs/tornado/tornado/websocket.py", line 121, in close
2011-10-26_23:58:30.12364         self.ws_connection.close()
2011-10-26_23:58:30.12365       File "/home/ubuntu/test/libs/tornado/tornado/websocket.py", line 497, in close
2011-10-26_23:58:30.12366         self._write_frame(True, 0x8, b(""))
2011-10-26_23:58:30.12366       File "/home/ubuntu/test/libs/tornado/tornado/websocket.py", line 400, in _write_frame
2011-10-26_23:58:30.12367         self.stream.write(frame)
2011-10-26_23:58:30.12367       File "/home/ubuntu/test/libs/tornado/tornado/iostream.py", line 213, in write
2011-10-26_23:58:30.12368         self._check_closed()
2011-10-26_23:58:30.12369       File "/home/ubuntu/test/libs/tornado/tornado/iostream.py", line 504, in _check_closed
2011-10-26_23:58:30.12370         raise IOError("Stream is closed")
2011-10-26_23:58:30.12371     IOError: Stream is closed