docs: public synchronized long prepareForTransmission()
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "prepareForTransmission");
  
        checkValid();
        valid = false;
  
        // Get the last buffer and flip it. Then we can simply return the list of buffers
        if (dataList.size() > 0)
        {
           WsByteBuffer buff = dataList.get(dataList.size() - 1);
           buff.flip();
        }
  
        long sendAmount = 0;
        for (int x = 0; x < dataList.size(); x++)
        {
           WsByteBuffer buff = dataList.get(x);
           sendAmount += buff.remaining();
        }
  
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "prepareForTransmission", Long.valueOf(sendAmount));
        return sendAmount;
     }