message: accept 0xffffffff offset for json crc
diff: @@ -140,6 +140,11 @@ void JSONDescriptorEndpoint::handle(const uint8_t* input, size_t input_length, S
  return;
  uint32_t offset = 0;
  read_le<uint32_t>(&offset, input);
  +
  + // If the offset is special value 0xFFFFFFFF, send back the JSON crc instead
  + if (offset == 0xffffffff) {
  + default_readwrite_endpoint_handler(&json_crc_, nullptr, 0, output);
  + } else {
  NullStreamSink output_with_offset = NullStreamSink(offset, *output);
  size_t id = 0;
  @@ -150,6 +155,7 @@ void JSONDescriptorEndpoint::handle(const uint8_t* input, size_t input_length, S
  application_endpoints_->write_json(id, &output_with_offset);
  write_string("]", &output_with_offset);
  }
  +}
  int BidirectionalPacketBasedChannel::process_packet(const uint8_t* buffer, size_t length) {
  LOG_FIBRE("got packet of length %d: \r\n", length);
  