Custom Memory Allocation

In the Unity Roadmap, it seemed to me that the CTO talked about the fact that custom memory allocation is present in Unity 2017. Do you know more about it? I couldn’t find any documentation related.

I am talking about this btw:

BTW I am happy to hear that it took few months to wrap their head around a true ECS, at least now we stop with this story that GameObject and Monobehaviours are good enough