deleteCredential method
Delete credential. Always sent on 'me' topic
Implementation
Future deleteCredential(String method, String value) {
var packet =
_packetGenerator.generate(packet_types.Del, topic_names.TOPIC_ME);
var data = packet.data as DelPacketData;
data.what = 'cred';
data.cred = {'meth': method, 'val': value};
packet.data = data;
return _send(packet);
}