public void Download(string txId)
{
txId = txId.Trim(' ', '\r', '\n');
var fileData = _block.GetSatoshiUploadedFile(txId);
if (fileData == null)
{
throw new InvalidDataException($"The transaction ID {txId} was not found");
}
// Now check for headers
var fileName = Path.Combine(Settings.Default.OutputPath, Path.ChangeExtension(txId, fileData.Extension));
File.Delete(fileName);
File.WriteAllBytes(fileName, fileData.Data);
_messages.Add($"File saved to {fileName}");
}