docs: def request(url, message):
      """Given a url (host:port) and a message, sends that message synchronously
      and returns the response."""
      s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
      host, port = url.split(':')
      port = int(port)
      s.connect((host, port))
      s.send(pack(message))
      data = s.makefile().read()
      s.close()
      return data