code: func (p *Pod) Pid() (int, error) {
  	if pid, err := p.readIntFromFile("pid"); err == nil {
  		return pid, nil
  	}
  	if pid, err := p.readIntFromFile("ppid"); err != nil {
  		return -1, err
  	} else {
  		return pid, nil
  	}
  }
docs: // Pid returns the pid of the stage1 process that started the pod.