docs: public void processAckExpected(ControlAckExpected ackExpMsg) throws SIResourceException 
    {
      if (tc.isEntryEnabled())
        SibTr.entry(tc, "processAckExpectedMessage", new Object[] { ackExpMsg });
      
      int priority = ackExpMsg.getPriority().intValue();
      Reliability reliability = ackExpMsg.getReliability();
      
      SIBUuid12 streamID = ackExpMsg.getGuaranteedStreamUUID();
      StreamSet streamSet = getStreamSet(streamID, true);
    
      InternalInputStream internalInputStream = null;
      synchronized(streamSet)
      {
        internalInputStream = (InternalInputStream) streamSet.getStream(priority, reliability);        
  
        // This may be the first message which has required this stream    
        if(internalInputStream == null && 
        (reliability.compareTo(Reliability.BEST_EFFORT_NONPERSISTENT) > 0))
        {
          internalInputStream = createStream(streamSet, priority, reliability);      
        }
      }
          
      internalInputStream.processAckExpected(ackExpMsg.getTick());
          
      if (tc.isEntryEnabled())
        SibTr.exit(tc, "processAckExpectedMessage");
    }