Getting zipball with Octokit is returning me null or invalid zip file

[NikolayIT]

I have the following code:

// ... client = new Client(...);
// some authentication logic...
// some other queries to GitHub that work correctly
var url = "https://api.github.com/repos/SomeOrg/SomePrivateRepo/zipball";
var response = await this.client.Connection.Get<byte[]>(new Uri(url),
                                                        new Dictionary<string, string>(),
                                                        null);
var data = response.Body;
var responseData = response.HttpResponse.Body;

Three problems:

1. data is null
2. responseData is of type string
3. when I try Encoding.ASCII.GetBytes(response.HttpResponse.Body.ToString()); I get invalid zip file

Am I doing something wrong or is it a bug?

[shiftkey]

Fixed in #792