*
 * https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses
 */
internal fun canonicalizeInetAddress(address: ByteArray): ByteArray {
  return when {
    isMappedIpv4Address(address) -> address.sliceArray(12 until 16)
    else -> address
  }
}

/** Returns true for IPv6 addresses like `0000:0000:0000:0000:0000:ffff:XXXX:XXXX`. */
private fun isMappedIpv4Address(address: ByteArray): Boolean {