Codegen silently skips some getters

Given data object:

```
@DataObject(generateConverter=true)
public class MyDo {
private Map> data;
... JsonObject ctor, toJson, getter/setter
}
```

The converter generated for it silently skips the `Map> getData()` method conversion, does not throw errors during build.

To me, this did not occur at all when service (that defines API using MyDo) used locally, all worked just fine. But once used remotely (via ProxyHelper.registerService), things suddenly broke naturally, as data was simply missing when sent over wire.

Is this intentional? As I got really puzzled where the data goes away?