libretto.scaletto.impl.futurebased

Executor of FreeScaletto based on Futures and Promises.

It is known to be flawed by design in that it might create long (potentially infinite) chains of Promises. This could be solved with a custom implementation of promises/futures that support unregistration of listeners.

On top of that, expect bugs, since the implementation is full of unsafe type casts, because Scala's (including Dotty's) type inference cannot cope with the kind of pattern matches found here.