CachingWithTTL.scala

def cachingWithTTL[T, M[_]](keyParts: Any*)(value: => M[(T, Duration)])
                           (implicit cache: Cache[T], mode: Mode[M], flags: Flags): M[T] = {
    import mode._
    M.flatMap(get(keyParts:_*)) {
      case Some(found) => M.pure(found)
      case None =>
        M.flatMap(value) {
          case (v, ttl) =>
            M.map(put(keyParts:_*)(v, Some(ttl)))(_ => v)
        }
    }
  }