code: func (p *Pod) IsSupervisorReady() bool {
  	s1rootfs, err := p.Stage1RootfsPath()
  	if err != nil {
  		return false
  	}
  	target, err := os.Readlink(filepath.Join(s1rootfs, "/rkt/supervisor-status"))
  	if err != nil {
  		return false
  	}
  	if target == "ready" {
  		return true
  	}
  
  	return false
  }
docs: // IsSupervisorReady checks if the pod supervisor (typically systemd-pid1)
  // has reached its ready state. All errors are handled as non-readiness.