isValidIPv4Address static method
Check if string is a valid IPv4 address
ip - The IP address to validate
Returns true if IPv4 address is valid
Implementation
static bool isValidIPv4Address(String ip) {
final ipv4Regex = RegExp(r'^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$');
return ipv4Regex.hasMatch(ip);
}