code: func (p *pluginGetter) Get(href string) (*bytes.Buffer, error) {
  	argv := []string{p.certFile, p.keyFile, p.cAFile, href}
  	prog := exec.Command(filepath.Join(p.base, p.command), argv...)
  	plugin.SetupPluginEnv(p.settings, p.name, p.base)
  	prog.Env = os.Environ()
  	buf := bytes.NewBuffer(nil)
  	prog.Stdout = buf
  	prog.Stderr = os.Stderr
  	prog.Stdin = os.Stdin
  	if err := prog.Run(); err != nil {
  		if eerr, ok := err.(*exec.ExitError); ok {
  			os.Stderr.Write(eerr.Stderr)
  			return nil, fmt.Errorf("plugin %q exited with error", p.command)
  		}
  		return nil, err
  	}
  	return buf, nil
  }
docs: // Get runs downloader plugin command