This was a terrible oversight, but the point of having a small native type for future was
for making them efficient. Still we were using one Eo object for dispatching per future
to dispatch new value. I could have gathered all the dispatch with just one object, but
at the end we do have one object that notify us of the loop iteration... the loop object!
And we have event on that object that we can rely to trigger the dispatching of future
without requiring any additional object. So let's do that instead.
Depends on D8566