isDNSAddr function
Implementation
bool isDNSAddr(MultiAddr a) {
if (a.components.isEmpty) return false;
final firstComponentProtocol = a.components.first.$1; // This is a Protocol object
return firstComponentProtocol.code == Protocols.dns4.code ||
firstComponentProtocol.code == Protocols.dns6.code ||
firstComponentProtocol.code == Protocols.dnsaddr.code;
// Note: Go's ma.P_DNS is not directly listed in the Dart Protocols class.
// Assuming dns4, dns6, and dnsaddr cover the intended DNS types.
}