MemoryError autobahn 21.3.1 / asyncio / windows10

hi
i use an usb device on windows 10 and i plublish an event, with just a timestamp, each time i receive new data. After a while, an MemoryError exception appears:
Traceback (most recent call last):
File “d:\Software\Miniconda3\lib\asyncio\events.py”, line 80, in _run
self._context.run(self._callback, *self._args)
File “C:…\device.py”, line 80, in _publish_data
comp.session.publish(‘acq.trigger’, stamp=t)
File “d:\Software\Miniconda3\lib\site-packages\autobahn\wamp\protocol.py”, line 1476, in publish
raise e
File “d:\Software\Miniconda3\lib\site-packages\autobahn\wamp\protocol.py”, line 1472, in publish
self._transport.send(msg)
File “d:\Software\Miniconda3\lib\site-packages\autobahn\asyncio\rawsocket.py”, line 319, in send
self.sendString(payload)
File “d:\Software\Miniconda3\lib\site-packages\autobahn\asyncio\rawsocket.py”, line 98, in sendString
self.transport.write(header)
File “d:\Software\Miniconda3\lib\asyncio\proactor_events.py”, line 366, in write
self._buffer.extend(data)
MemoryError

any idea ?
thanks