internal static class Perm_AppData
{
    private static string[] scopes = { DriveService.Scope.DriveFile };
    private static DriveService service = Autorization();
    internal static DriveService Service { get { return service; } }

    private static DriveService Autorization()
    {
        UserCredential credential;

        using (var stream = GetCliSecStream())
        {
            credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.Load(stream).Secrets,
                scopes,
                "user",
                CancellationToken.None,
                new FileDataStore(auth, true)).Result;
        }

        return new DriveService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = applicationName
        });
    }

    private static Stream GetCliSecStream()
    {
        var stream = new MemoryStream();
        var writer = new StreamWriter(stream);
        writer.Write(uSec);
        writer.Flush();
        stream.Position = 0;
        return stream;
    }
}

internal static MemoryStream DownloadFile(string fileId = null, string fileName = null)
{
    using (new Watcher($"Download {fileName} {fileId}"))
    {
        GetRequest request = null;
        if (fileId != null)
        {
            request = service.Files.Get(fileId);
        }
        else
        {
            if (fileName != null)
            {
                request = service.Files.Get(ViewDrive(SearchParameter.name, new string[] { fileName }).First().Id);
            }
            else
            {
                throw new Exception("You need at least one not null parameter to download");
            }
        }

        request.Fields = "id, name";
        var fileMemoryStream = new MemoryStream();
        request.Download(fileMemoryStream);
        return fileMemoryStream;
    }
}

WebRequest.DefaultWebProxy.Credentials = CredentialCache.DefaultNetworkCredentials;