Spreadsheets API Can not update a read-only feed

I'm trying to add new spreadsheet if it not exists with GData Spreadsheet API for .NET but it gives me following exception:

Can not update a read-only feed

Here's my code:

    var service = new SpreadsheetsService("<my-app>");
    service.setUserCredentials("<login>", "<password>");

    // Instantiate a SpreadsheetQuery object to retrieve spreadsheets.
    SpreadsheetQuery query = new SpreadsheetQuery();
    var title = "test";
    query.Title = title;

    // Make a request to the API and get all spreadsheets.
    SpreadsheetFeed feed = service.Query(query);

    if (!feed.Entries.Any())
    {
        var worksheet = new WorksheetEntry(20, 20, title);
        service.Insert(feed, worksheet);             
    }

Through Fiddler I see that I'm doing request to:

GET /feeds/spreadsheets/private/full?title=test

and it goes fine, but I don't see any requests for updating data. I suppose that I should change somehow SpreadsheetQuery to make it capable to write data, but I can't find how.

It's me being inattentive because google documentation on Spreadsheet API says:

It is possible to create a new spreadsheet by uploading a spreadsheet file via the Google Drive API. The Spreadsheets API does not currently provide a way to delete a spreadsheet, but this is also provided in the Google Drive API. For testing purposes, you may create a spreadsheet manually or upload one.

So I basically installed GoogleDrive API with Nuget. And then added following method for adding file:

private static void AddFile(string title)
{
    var clientID = "put here a clientID";
    var clientSecret = "put here a clientSecret";

    UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
        new ClientSecrets
        {
            ClientId = clientID,
            ClientSecret = clientSecret,
        },
        new[] { DriveService.Scope.Drive },
        "here goes your account",
        CancellationToken.None).Result;

    // Create the service.
    var service = new DriveService(new BaseClientService.Initializer()
    {
        HttpClientInitializer = credential,
        ApplicationName = "Drive API Sample",
    });

    var body = new Google.Apis.Drive.v2.Data.File();
    body.Title = title;
    //body.Description = "A test document";
    body.MimeType = "application/vnd.google-apps.spreadsheet";

    service.Files.Insert(body).Execute();
}

When I run code above at the first time - I received an exception that said

Could not load file or assembly 'Microsoft.Threading.Tasks.Extensions.Desktop, Version=1.0.16.0

I run these in Package Manager Console:

Uninstall-Package Microsoft.Bcl.Async -Force
Install-Package Microsoft.Bcl.Async

and it worked. Hope it would help somebody who will stumble over the same issue.