public interface Api {
@POST("api/v4/persons")
Observable<Person> createPerson(@Body Person person);
@PUT("api/v4/persons/{id}")
Observable<Person> updatePerson(@Path("id") int personId, @Body Person person);
}
public Api create()
{
Retrofit retrofit = new Retrofit.Builder()
...
.addConverterFactory(GsonConverterFactory.create(createGson()))
....
.build();
return retrofit.create(Api.class);
}