how to time out a scala future

scalaFutureTimeout.scala

val realFuture = Future(doRealStuff())
//timeoutFuture does a spin wait by sleeping on the thread on which it runs, so make sure the ExecutionContext
//on which it runs is multi-threaded. In an akka based environment, use a scheduler to fulfill a promise with a failure
//when the timeout duration is complete, and avoid the spin wait
val timeoutFuture = Future {
  Thread.sleep(timeoutMilliseconds)
  throw new TimeoutException("timeout")
}
Future.firstCompletedOf(realFuture :: timeoutFuture :: Nil)