Question about one of the flags packed in NetEvents.

Inside NetConnection::eventWritePacket () there's a while loop that looks like this:

while(mUnorderedSendEventQueueHead)
   {
      if(bstream->isFull())
         break;
      // dequeue the first event
      NetEventNote *ev = mUnorderedSendEventQueueHead;
      mUnorderedSendEventQueueHead = ev->mNextEvent;
      U32 start = bstream->getCurPos();

      bstream->writeFlag(true);

See that last part? Why is it written out? Seems to me like it's not used.
Edit: Nevermind.. it's used to break out of the while loop in eventReadPacket. Perhaps if the packet is unordered?