examples_ipv6_outgoing_multicast_interface.md

On most systems, where scope format uses the interface name:

```js
const socket = dgram.createSocket('udp6');

socket.bind(1234, () => {
  socket.setMulticastInterface('::%eth1');
});
```

On Windows, where scope format uses an interface number:

```js
const socket = dgram.createSocket('udp6');

socket.bind(1234, () => {
  socket.setMulticastInterface('::%2');
});
```