Customizing Loading Sub-state Behavior


I am wondering if anyone has implemented any customized loading substates?

The default behavior, when the store is returning a promise, is to transition (eager) into a loading template while the promise resolves…

I would rather, like to have a lazy style transition, so the original template remains visible but create a transparent overlay, displaying my “loading widget”. the goal is not to have that split second flash where the old template goes away, see the “loading” screen and then jump into the new page.

Its seems to be a common convention online, but not sure how to recreate it in Ember…

Does anyone have some insight into how I can accomplish this behavior?