class Net::InternetMessageIO

def each_message_chunk
  LOG 'reading message...'
  LOG_off()
  read_bytes = 0
  while (line = readuntil("\r\n")) != ".\r\n"
    read_bytes += line.size
    yield line.delete_prefix('.')
  end
  LOG_on()
  LOG "read message (#{read_bytes} bytes)"
end