code: func (n *NIC) Addresses() []tcpip.ProtocolAddress {
  	n.mu.RLock()
  	defer n.mu.RUnlock()
  	addrs := make([]tcpip.ProtocolAddress, 0, len(n.endpoints))
  	for nid, ep := range n.endpoints {
  		addrs = append(addrs, tcpip.ProtocolAddress{
  			Protocol: ep.protocol,
  			Address:  nid.LocalAddress,
  		})
  	}
  	return addrs
  }
docs: // Addresses returns the addresses associated with this NIC.