public void tellSubscribers( Actor sender, String topic, Object message) {
        List<ReceiverActor> subscriber = topic2Subscriber.get(topic);
        if ( subscriber != null ) {
            subscriber.stream()
                .filter(subs -> !subs.equals(sender)) // do not receive self sent
                .forEach(subs -> subs.receiveTell(topic, message) );
        }
    }
public void tellSubscribers ( Actor sender , String topic , Object message ) { List < ReceiverActor > subscriber = topic2Subscriber . get ( topic ) ; if ( subscriber != null ) { subscriber . stream ( ) . filter ( subs -> ! subs . equals ( sender ) ) . forEach ( subs -> subs . receiveTell ( topic , message ) ) ; } }
send a fire and forget message to all

@param sender
@param topic
@param message