Is the point of this just to get a unique path to use?

Yes, could make a comment about this.

we don't care about putting these anywhere specific in case of issues where files aren't cleaned up or something? Maybe in the C:\ContainerPlatData dir like the container IO files or something?

I don't think we should place them in a directory containerd maintains, but I'm not too worried about this in general. The way we setup the io channels is to just close the listener the second we accept a connection (which removes the socket file anyways).

Could you explain why not?

The socket file itself is removed the second you'd close the listener, but the connection is still valid. For a quick hacked up example.

func echo(c net.Conn) {
	for {
		buf := make([]byte, 512)
		nr, err := c.Read(buf)
		if err != nil {
			log.Fatal(err)
		}

		data := buf[0:nr]
		fmt.Printf("Received: %v\n\n", string(data))
	}
}

func main() {
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT)

	l, err := net.Listen("unix", `/test.sock`)
	if err != nil {
		log.Fatal(err)
	}

	conn, err := l.Accept()
	if err != nil {
		log.Fatal(err)
	}

	// Socket file removed after this line, can still utilize the conn we have but the listeners
	// done for (can't accept any further conns).
	l.Close()

	go echo(conn)

	select {
	case <-sigChan:
		log.Print("Received signal, closing.")
	}
}

Where the listener we return in this func is eventually used is here: https://github.com/microsoft/hcsshim/blob/master/internal/gcs/iochannel.go#L14-L27

So I don't have many worries about socket files not being cleaned up.