A right biased union type that holds a value for an asynchronous/future successful computation or a value for a failed one.
It's a wrapper around Future[Result[A, B]]. Most of the functionality delegates to
the underlying Result which is inside of the future. It does provide a flatMap
instance which allows it to be used in a for comprehension.
It's an alternative to Future and very similar (but with much less functionality)
to Task in Scalaz.