Token Refresher with lazy Future

Token.scala

class Token() {
  def newToken(): Eval[Future[AccessToken]] = Eval.later(Future(???))
  
  val tokenRef: AtomicReference[Eval[Future[AccessToken]]] = AtomicReference(newToken())
  
  def get(): Future[AccessToken] = {
    val eval = tokenRef.get()
    eval.value.flatMap { token =>
      if (token.isExpiring) {
        tokenRef.compareAndSet(eval, newToken())
        tokenRef.get().value
      } else {
        Future.successful(token)
      }
    }
  }
}