Use with /dev/net/tun

[Yamakaky]

To add a new TUN/TAP device, you have to open /dev/net/tun, configure it with ioctl then read/select it like a normal fd. Would it be appropriate for use with UnixDatagram? If so, did you consider adding impl FromRawFd for UnixDatagram?

[alexcrichton]

It's plausible that a FromRawFd method could be added but are the relevant methods appropriate? I haven't worked with TUN/TAP much but do those basically look like unix sockets? (e.g. also in sockaddrs received)