duplicateFuture.scala

def f() = Future{
  sleep(2000)
  println "Calling future."
  "Hello World!"
}

def time[A](title: String)(fut: => Future[A])(implicit context: ExecutionContext):Future[A] = {
  val timer = System.currentTimeMillis()
  fut.onComplete(_ => 
    println(s"""${title} took: ${System.currentTimeMillis-timer} ms to complete.""")
  )
  fut
}

val e = time("test future"){f()}.either()

e match {
  case Right(s) => println(s)
  case Left(e) => e.printStackTrace
}