checkAtsign method
checks receiver
is a valid atsign
Implementation
Future<bool> checkAtsign(String receiver,
{String root = 'root.atsign.org'}) async {
// ignore: unnecessary_null_comparison
if (receiver == null) {
return false;
} else if (!receiver.contains('@')) {
receiver = '@$receiver';
}
var checkPresence = (await CacheableSecondaryAddressFinder(root, 64)
.findSecondary(receiver))
.toString();
return checkPresence.isNotEmpty;
}