web api 中文输出文件是文件名乱码?

[colindcli]

/// <summary>
/// API Response
/// </summary>
/// <param name="bt"></param>
/// <param name="fileName"></param>
public static HttpResponseMessage ResponseFile(byte[] bt, string fileName)
{
    var response = new HttpResponseMessage { Content = new ByteArrayContent(bt) };
    response.Content.Headers.ContentLength = bt.Length;
    response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
    {
        FileName = fileName,
        FileNameStar = fileName //IE、firefox文件名乱码问题
    };
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
    return response;
}

https://github.com/colindcli/CodeGit/blob/master/Http/Response.cs