docs: def supervisor_events(stdin, stdout):
      """
      An event stream from Supervisor.
      """
  
      while True:
          stdout.write('READY\n')
          stdout.flush()
  
          line = stdin.readline()
          headers = get_headers(line)
  
          payload = stdin.read(int(headers['len']))
          event_headers, event_data = eventdata(payload)
  
          yield event_headers, event_data
  
          stdout.write('RESULT 2\nOK')
          stdout.flush()