type UserId = string
type Name = string

type User = {
  id: string,
  name: string,
  active: boolean
}

error UserMissing = { id: string }
error StoreUnavailable = { message: string }

service Users {
  find(id: UserId): Option<User> fails StoreUnavailable
  save(user: User): void fails StoreUnavailable
  all(): User[] fails StoreUnavailable
}

export const lookupWithRetry = (id: UserId): Option<User>
  fails StoreUnavailable
  uses Users.find =>
  retry(() => Users.find(id), { times: 2 })