code: func IsV4MappedAddress(addr tcpip.Address) bool {
  	if len(addr) != IPv6AddressSize {
  		return false
  	}
  
  	return strings.HasPrefix(string(addr), "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff")
  }
docs: // IsV4MappedAddress determines if the provided address is an IPv4 mapped
  // address by checking if its prefix is 0:0:0:0:0:ffff::/96.