code: private int available()
    {
      long sent = sent();
      
      int available = Math.max(0, (int) (_creditsIn - sent));
      
      available = Math.min(available, _queue.remainingCapacity());
      
      if (available <= 0) {
        outFull();
      }
  
      return available;
    }
docs: /*
  @Override
  public FlowIn flow()
  {
  return _inFlow;
  }