toPacket method
toPacket returns the packet in the format of Layrz Link Protocol v2.
Implementation
@override
String toPacket() {
String payload = devices.map((e) => e.toPacket()).join(';');
payload += ';';
String crc = calculateCrc(payload.codeUnits).toRadixString(16).padLeft(4, '0').toUpperCase();
return '<Ab>$payload$crc</Ab>';
}