call callback for all data forever (until \C-c)

        :param use_thread: use thread for spin (do not block)

def spin(self, use_thread=False):
        '''call callback for all data forever (until \C-c)

        :param use_thread: use thread for spin (do not block)
        '''
        if use_thread:
            if self._thread is not None:
                raise 'spin called twice'
            self._thread = threading.Thread(target=self._spin_internal)
            self._thread.setDaemon(True)
            self._thread.start()
        else:
            self._spin_internal()