code: private void enqueueAvailableReader(final NetworkSequenceViewReader reader) throws Exception {
  		if (reader.isRegisteredAsAvailable() || !reader.isAvailable()) {
  			return;
  		}
  		// Queue an available reader for consumption. If the queue is empty,
  		// we try trigger the actual write. Otherwise this will be handled by
  		// the writeAndFlushNextMessageIfPossible calls.
  		boolean triggerWrite = availableReaders.isEmpty();
  		registerAvailableReader(reader);
  
  		if (triggerWrite) {
  			writeAndFlushNextMessageIfPossible(ctx.channel());
  		}
  	}
docs: Try to enqueue the reader once receiving credit notification from the consumer or receiving
  non-empty reader notification from the producer.
  
  <p>NOTE: Only one thread would trigger the actual enqueue after checking the reader's
  availability, so there is no race condition here.