message: Fix datalink pcap backend
diff: @@ -168,7 +168,7 @@ struct DataLinkReceiverImpl<T: Activated + Send + Sync> {
  impl<T: Activated + Send + Sync> DataLinkReceiver for DataLinkReceiverImpl<T> {
  fn next(&mut self) -> io::Result<&[u8]> {
  let mut cap = self.capture.lock().unwrap();
  - match cap.next() {
  + match cap.next_packet() {
  Ok(pkt) => {
  self.read_buffer.truncate(0);
  self.read_buffer.extend(pkt.data);
  