public void subscribe(long clientId, NamespaceEvent subscribedEvent,
long txId) throws InvalidClientIdException, TransactionIdTooOldException,
TException {
core.getMetrics().subscribeCalls.inc();
if (!core.isRegistered(clientId)) {
throw new InvalidClientIdException("Invalid client id: " + clientId);
}
core.subscribeClient(clientId, subscribedEvent, txId);
}