Code speaks louder than comments:

```scala
// TODO move to Try for 2.11.0
def transformTry[A](v: Try[A, B)])(f => Throwable => Throwable, s: A => B = v match {
  case Success(r) => Try(s(r))
  case Failure(t) => Try(f(t)) // will throw fatal errors!
}
onComplete { try => transformTry(try)(f, s) }
```