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Problems could arise not only in realtime context but, for example if you have not a real duplex communication, but half duplex. I meet situation when controlled equipment was half duplex, and when you send something at that time when it trying to send something it simple die! We putting reasonably large timouts bettween packets but because of the asynchronizm caused by buffers it is still dieing at least once a week. There are a lot of solutions for these kind of situation, but it was a third party equipment we can not change this behavior!