code: def _send_accum_trace(self, device_uuid):
          
  
          if device_uuid not in self._connections:
              self._logger.debug("Dropping trace data for device without an active connection, uuid=0x%X", device_uuid)
              return
  
          conn_data = self._connections[device_uuid]
  
          trace = conn_data['trace_accum']
  
          if len(trace) > 0:
              slug = self._build_device_slug(device_uuid)
              tracing_topic = self.topics.prefix + 'devices/{}/data/tracing'.format(slug)
  
              data = {'type': 'notification', 'operation': 'trace'}
              data['trace'] = binascii.hexlify(trace)
              data['trace_origin'] = device_uuid
  
              self._logger.debug('Publishing trace: (topic=%s)', tracing_topic)
              self.client.publish(tracing_topic, data)
  
          conn_data['trace_scheduled'] = False
          conn_data['last_trace'] = monotonic()
          conn_data['trace_accum'] = bytes()
docs: Send whatever accumulated tracing data we have for the device.