code: func (e EnvVar) String() string {
  	b := bytes.NewBuffer(nil)
  	for _, env := range e {
  		// don't include invalid strings
  		if len(strings.SplitN(env, "=", 2)) < 2 {
  			continue
  		}
  		fmt.Fprintln(b, env)
  	}
  	return b.String()
  }
docs: // String returns key=val format of the environment variables.
  // Each on a line.