private void continueReadIfPossible(long delta) {
    if (!channel.config().isAutoRead()) {
      if (bytesBuffered.addAndGet(delta) < bufferWatermark) {
        channel.read();
      } else {
        nettyMetrics.watermarkOverflowCount.inc();
      }
    }
  }
Invokes a read from the read channel if the number of bytes buffered is below the buffer watermark. No effect if
auto-read is on.
@param delta number of bytes read from the read channel in the current read (positive) or number of bytes written
             to the write channel in the current write (negative).
ambry-rest/src/main/java/com/github/ambry/rest/NettyRequest.java