docs: public void requestMoreMessages(int receivedBytes, int requestedBytes)
        throws SIConnectionDroppedException, SIConnectionLostException
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "requestMoreMessages",
                                             new Object[]{""+receivedBytes, ""+requestedBytes});
  
        if (sessionId == 0)
        {
           // If the session Id = 0, then no one called setSessionId(). As such we are unable to flow
           // to the server as we do not know which session to instruct the server to use.
           SIErrorException e = new SIErrorException(
              nls.getFormattedMessage("SESSION_ID_HAS_NOT_BEEN_SET_SICO1043", null, null)
           );
  
           FFDCFilter.processException(e, CLASS_NAME + ".requestMoreMessages",
                                       CommsConstants.CONVERSATIONHELPERIMPL_07, this);
  
           if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) SibTr.debug(this, tc, e.getMessage(), e);
  
           throw e;
        }
  
        CommsByteBuffer request = getCommsByteBuffer();
        // Connection object id
        request.putShort(connectionObjectId);
        // Consumer session id
        request.putShort(sessionId);
        // Received bytes
        request.putInt(receivedBytes);
        // Requested bytes
        request.putInt(requestedBytes);
  
        // Pass on call to server
        jfapSend(request,
                 JFapChannelConstants.SEG_REQUEST_MSGS,
                 JFapChannelConstants.PRIORITY_MEDIUM,
                 true,
                 ThrottlingPolicy.BLOCK_THREAD);
  
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "requestMoreMessages");
     }