code: public synchronized boolean flushable()
    {
      TickRange range = new TickRange(TickRange.Unknown, 0, RangeList.INFINITY);
  
      return (
        (!oststream.containsState(range, TickRange.Value))
          && (!oststream.containsState(range, TickRange.Uncommitted))
          && (!oststream.containsState(range, TickRange.Error)));
    }
docs: Check if this stream is flushable.  A stream is flushable if
  there are no V/U or L/U ticks.
  
  @return true if there are currently no V/U or L/U ticks, and
  false otherwise.