void E2Sim::register_subscription_callback(long func_id, SubscriptionCallback cb) {
fprintf(stderr,"%%%%about to register callback for subscription for func_id %d\n", func_id);
subscription_callbacks[func_id] = cb;
void E2Sim::register_subscription_callback(long func_id, SubscriptionCallback cb) {
fprintf(stderr,"%%%%about to register callback for subscription for func_id %d\n", func_id);
subscription_callbacks[func_id] = cb;