private void enqueueSend(){
  final int currentOutstanding=outstanding.get();
  if (currentOutstanding < concurrency) {
    sendBatch();
    return;
  }
  pending=true;
  pendingTopics.offer(this);
  listener.topicPending(Publisher.this,topic,currentOutstanding,concurrency);
  sendPending();
}

private void enqueueSend ( ) { final int currentOutstanding = outstanding . get ( ) ; if ( currentOutstanding < concurrency ) { sendBatch ( ) ; return ; } pending = true ; pendingTopics . offer ( this ) ; listener . topicPending ( Publisher . this , topic , currentOutstanding , concurrency ) ; sendPending ( ) ; }
enqueue this topic for batch sending . if the request concurrency level is below the limit , send immediately .
