You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: svcb.go
    path of file: ./repos/scan4all/vendor/github.com/miekg/dns
    
    the code of the file until where you have to start completion: package dns

import (
	"bytes"
	"encoding/binary"
	"errors"
	"fmt"
	"net"
	"sort"
	"strconv"
	"strings"
)

// SVCBKey is the type of the keys used in the SVCB RR.
type SVCBKey uint16

// Keys defined 
    
func (s *SVCBIPv6Hint) unpack(b []byte) error {
	if len(b) == 0 || len(b)%16 != 0 {
		return errors.New("dns: svcbipv6hint: ipv6 address byte array length not a multiple of 16")
	}
	b = cloneSlice(b)
	x := make([]net.IP, 0, len(b)/16)
	for i := 0; i < len(b); i += 16 {
		ip := net.IP(b[i : i+16])
		if ip.To4() != nil {
			return errors.New("dns: svcbipv6hint: expected ipv6, got ipv4")
		}
		x = append(x, ip)
	}
	s.Hint = x
	return nil
}