code: public boolean isEmpty()
    {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
      {
        SibTr.entry(this, tc, "isEmpty");
        SibTr.exit(tc, "isEmpty", new Object[] {Boolean.valueOf(streamSets.isEmpty()), 
            Boolean.valueOf(flushedStreamSets.isEmpty()),streamSets, this});
      }
  
      // Don't report empty until any pending flushes have completed.
      // Otherwise we may run into a race with an async delete thread
      // for the destination.
      return (streamSets.isEmpty() && flushedStreamSets.isEmpty());
    }
docs: Determine if there are any unflushed target streams to the destination
  
  @return boolean