code: func AddressCount(network *net.IPNet) uint64 {
  	prefixLen, bits := network.Mask.Size()
  	return 1 << (uint64(bits) - uint64(prefixLen))
  }
docs: // AddressCount returns the number of distinct host addresses within the given
  // CIDR range.
  //
  // Since the result is a uint64, this function returns meaningful information
  // only for IPv4 ranges and IPv6 ranges with a prefix size of at least 65.