code: def exit(self, result=PANTS_SUCCEEDED_EXIT_CODE, msg=None, out=None):
      
      if msg:
        out = out or sys.stderr
        if PY3 and hasattr(out, 'buffer'):
          out = out.buffer
  
        msg = ensure_binary(msg)
        try:
          out.write(msg)
          out.write(b'\n')
          # TODO: Determine whether this call is a no-op because the stream gets flushed on exit, or
          # if we could lose what we just printed, e.g. if we get interrupted by a signal while
          # exiting and the stream is buffered like stdout.
          out.flush()
        except Exception as e:
          # If the file is already closed, or any other error occurs, just log it and continue to
          # exit.
          if msg:
            logger.warning("Encountered error when trying to log this message: {}".format(msg))
            # In pantsd, this won't go anywhere, because there's really nowhere for us to log if we
            # can't log :(
            # Not in pantsd, this will end up in sys.stderr.
            traceback.print_stack()
          logger.exception(e)
      self._exit(result)
docs: Exits the runtime.
  
      :param result: The exit status. Typically either PANTS_SUCCEEDED_EXIT_CODE or
                     PANTS_FAILED_EXIT_CODE, but can be a string as well. (Optional)
      :param msg: A string message to print to stderr or another custom file desciptor before exiting.
                  (Optional)
      :param out: The file descriptor to emit `msg` to. (Optional)