Futures vs eventbase

This is more of a question than an issue. If there are appropriate newbie mailers setup for this purpose, please let me know.

Futures vs eventbase

Are these competing or can they be used together?

Is future “via executor” typically a CPUexecutor? Or can it use IOexector too? When would you go via the IO executor? Probably never?

If a eventbase thread wants to wait on a future, where does that waiting happen? Is it handled by eventFD and notification queue mechanism in the eventbase thread?

So is it fair to say that future and then’ning should be done from eventbase thread because there you have a eventbase that will handle the “then” scheduling?

If you create a .then chain from a CPUexecutor, how would the scheduling happen? Does it even make sense?