code: func (l *State) Metadata() map[string]string {
  	l.RLock()
  	defer l.RUnlock()
  
  	m := make(map[string]string)
  	for k, v := range l.metadata {
  		m[k] = v
  	}
  	return m
  }
docs: // Metadata returns the local node metadata fields that the
  // agent is aware of and are being kept in sync with the server