deleteMessagesAll method
Delete all messages. Hard-deleting messages requires Owner permission
Implementation
Future<CtrlMessage> deleteMessagesAll(bool hard) {
if (_maxSeq == 0 || _maxSeq <= 0) {
// There are no messages to delete.
return Future.value();
}
return deleteMessages([DelRange(low: 1, hi: _maxSeq + 1, all: true)], hard);
}