termecho1.pony

class MyNotify
  let env: Env

  new create(env': Env) =>
    env = env'
  
  fun ref apply(data: Array[U8] iso) =>
    env.out.print(consume data)

  fun ref dispose() =>
    None

actor Main
  new create(env: Env) =>
    env.input(recover iso MyNotify.create(env) end)

termecho2.pony

class MyNotify
  let env: Env

  new iso create(env': Env) =>
    env = env'
  
  fun ref apply(data: Array[U8] iso) =>
    env.out.print(consume data)

  fun ref dispose() =>
    None

actor Main
  new create(env: Env) =>
    env.input(MyNotify.create(env))