message: example-ftp: Do not divide by zero on zero-bytes file
diff: @@ -133,7 +133,9 @@ download_file(Ftp& ftp, const std::string& remote_file_path, const std::string&
  ftp.download_async(
  remote_file_path, local_path, [&prom](Ftp::Result result, Ftp::ProgressData progress) {
  if (result == Ftp::Result::Next) {
  - int percentage = progress.bytes_transferred * 100 / progress.total_bytes;
  + int percentage = progress.total_bytes > 0 ?
  + progress.bytes_transferred * 100 / progress.total_bytes :
  + 0;
  std::cerr << "\rDownloading [" << std::setw(3) << percentage << "%] "
  << progress.bytes_transferred << " of " << progress.total_bytes;
  if (progress.bytes_transferred >= progress.total_bytes) {
  @@ -156,7 +158,9 @@ upload_file(Ftp& ftp, const std::string& local_file_path, const std::string& rem
  ftp.upload_async(
  local_file_path, remote_path, [&prom](Ftp::Result result, Ftp::ProgressData progress) {
  if (result == Ftp::Result::Next) {
  - int percentage = progress.bytes_transferred * 100 / progress.total_bytes;
  + int percentage = progress.total_bytes > 0 ?
  + progress.bytes_transferred * 100 / progress.total_bytes :
  + 0;
  std::cerr << "\rUploading "
  << "[" << std::setw(3) << percentage << "%] "
  << progress.bytes_transferred << " of " << progress.total_bytes;
  