I like very much the feature called "nested loading" in the new data package and I was wondering, will there be a similar "nested saving" feature?

Assume you have a User model, which has many associated Posts. Now, when you load a user through a configured proxy you also get its posts. If the server can spell it out, the data package is smart enough to create a posts store (configured with a memory proxy I assume) in the user model.

If you modify/delete any of the posts or add a new one, and then call User.save(), will it also send the nested posts to the server? Something like this (assuming a rest/json proxy):

users.json - PUT:
Code:
{
	"id":		1,
	"name":	"John Doe",
	"email":	"john.doe@example.com",
	"posts": [
		{ "id": 1, "message": "first post message" },
		{ "id": 2, "message": "second post message" },
		{ "id": 3, "message": "third post message" }
	]
}
Would be nice to have something like this, plus in some types of applications would be a must-have (for instance when you have to save the changes to a database in an atomic transaction).

If "nested saving" will not be provided by the API in Ext 4.0, any suggestions on how to implement such a feature in the application code?