client.ex

  def init(conn) do
    Process.flag :trap_exit, true

    {ip, port} = conn |> Socket.remote!
    host = case Socket.Host.by_address(ip) do
             {:ok, _host} ->
               _host.name

             {:error, _} ->
               Socket.Address.format ip
           end
    {listener, secure} =
    case nil? conn.listener do
      true ->
        {nil, nil}

      false ->
        {conn.listener, conn.listener.secure}
    end
    {:ok, conn}
  end