ConnectionState cs = lookupConnectionState(connectionId);
SessionState ss = cs.getSessionState(sessionId);
if( ss == null )
throw new IllegalStateException("Cannot remove a producer from a session that had not been registered: "+sessionId);
ProducerState ps = ss.removeProducer(id);
if( ps == null )
throw new IllegalStateException("Cannot remove a producer that had not been registered: "+id);
broker.removeProducer(cs.getContext(), ps.getInfo());
return null;