simulation.sc

case class UserInfo(userId: Int, nickname: String, emailAddress: String, account: Option[Long])

def getNicknameById(userId: Int): Future[String] = Future {
  Thread.sleep(2000)
  "ktz"
}

def getEmailAddressByNickname(nickname: String): Future[String] = Future {
  Thread.sleep(2000)
  "helloworld@example.com"
}

def getAccountInfoByNickname(nickname: String): Future[Option[Long]] = Future {
  Thread.sleep(3000)
  None
}

def printInterval(userInfo: UserInfo, start: Instant, end: Instant): String =
  s"$userInfo take ${(end.toEpochMilli - start.toEpochMilli) / 1000} seconds"

val userId: Int = 31337