actor Log
  let logger: Logger[String]

  new create(env: Env) =>
    this.logger = StringLogger(Warn, env.out)

  be msg(str: String) =>
    this.logger(Warn) and this.logger.log(str)

actor Server
  let log: Log
  let reg: Registrar

  new create(env: Env) =>
    this.log = Log(env)
    this.reg = Registrar
    this.reg("log") = Log(env)
    let promise = this.reg[Log]("log")
    promise.next[None](
      recover iso
        lambda(value: Log)(self=this) => value.msg("hlay")
        end
      end)