<@U0GGKKPUZ> definitely not worth it. I went with...

# announcements

[kirillrakhman]

@mk definitely not worth it. I went with

interface FutureCallback<out E> {
   operator fun <T> invoke(f: (E) -> T): Future<T>
}

and an anonymous object that implements it. my biggest remaining pain is that I can't implement the interface with a lambda. note that the problem is not SAM conversion but the fact that lambdas can't be generic.