Example of using PageStreamer on Files.list with Google Drive v3

GoogleDriveV3PageStreamer

var pageStreamer = new PageStreamer<Google.Apis.Drive.v3.Data.File, FilesResource.ListRequest, Google.Apis.Drive.v3.Data.FileList, string>(
                                                   (request, token) => request.PageToken = token,
                                                   response => response.NextPageToken,
                                                   response => response.Files);
           
var req = service.Files.List();
req.PageSize = 1000;

foreach (var result in pageStreamer.Fetch(req))
  {
    Console.WriteLine(result.Id);
  }          

as soon as I add the line
req.Fields = "files(id, name, parents, permissions, kind)";

then only 100 entries are returned??