go-endpoint Invalid date format and method not found - google-app-engine

Question

Hy, I have some problems with the Go endpoints and Dart client library.
I use the Go library https://github.com/crhym3/go-endpoints and the dart generator https://github.com/dart-lang/discovery_api_dart_client_generator
The easy examples works fine. But they show never how to use time.Time.
In my project, I have a struct with a field:
Created time.Time `json:"created"`
The output in the explorer looks like this:
"created": "2014-12-08T20:42:54.299127593Z",
When i use it in the dart client library, I get the error
FormatException: Invalid date format 2014-12-08T20:53:56.346129718Z
Should I really format every time fields in the go app (Format Timestamp in outgoing JSON in Golang?)?
My research come to that the dart accept something:
t.Format(time.RFC3339) >> 2014-12-08T20:53:56Z
Second problem, if comment out the Created field or leave it blank. I get a other error:
The null object does not have a method 'map'.
NoSuchMethodError: method not found: 'map' Receiver: null Arguments:
[Closure: (dynamic) => dynamic]
But I can't figure it out which object is null. I'm not sure if I'm using the Dart client correct
import 'package:http/browser_client.dart' as http;
...
var nameValue = querySelector('#name').value;
var json = {'name':nameValue};
LaylistApi api = new LaylistApi(new http.BrowserClient());
api.create(new NewLayListReq.fromJson(json)).then((LayList l) {
print(l);
}).catchError((e) {
querySelector('#err-message').innerHtml=e.toString();
});
Does anyone know of a larger project on github with Go endpoint and Dart?
Thanks for any advice
UPDATE[2014-12-11]:
I fixed the
NoSuchMethodError
with the correct discovery url https://constant-wonder-789.appspot.com/_ah/api/discovery/v1/apis/greeting/v1/rest
The problem with the time FormatExcetion still open, but I'm one step further. If i create a new item, it doesn' work. But if I load the items from the datastore and send it back, this works.
I guess this can be fixed with implementing Marshaler interface, thanks Alex. I will update my source soon.
See my example:
http://constant-wonder-789.appspot.com/
The full source code:
https://github.com/cloosli/greeting-example