Observations

trait TimeReader {

  def currentTime: Long = System.currentTimeMillis

  def flowOfTime = Iterator.iterate(currentTime){_ => currentTime}

  def interval(n:Long) = {
    flowOfTime.next // the first drop, may be stale
    val end = flowOfTime.next + n
    flowOfTime takeWhile (end >)
  }

  def interval(duration: Duration) = interval(duration.toMillis)
  //...

for {i <- 1 to 10; t <- interval(1 second) } {Thread.sleep(1); println(s"$i @$t") }