parseIPv4Address method
Parse the host as an IP version 4 (IPv4) address, returning the address
as a list of 4 bytes in network byte order (big endian).
Throws a FormatException if host is not a valid IPv4 address
representation.
Implementation
static List<int> parseIPv4Address(String host) =>
_parseIPv4Address(host, 0, host.length);