node.go
func NodeID() []byte {
	defer nodeMu.Unlock()
	nodeMu.Lock()
	if nodeID == zeroID {
		setNodeInterface("")
	}
	nid := nodeID
	return nid[:]
}
func NodeID() []byte {
	defer nodeMu.Unlock()
	nodeMu.Lock()
	if nodeID == zeroID {
		setNodeInterface("")
	}
	nid := nodeID
	return nid[:]
}
// NodeID returns a slice of a copy of the current Node ID, setting the Node ID
// if not already set.