@Override
 public void fireChannelInactive() {
   // Some implementations such as EmbeddedChannel can trigger inboundBufferUpdated()
   // after deactivation, so it's safe not to revert the firedChannelActive flag here.
   // Also, all known transports never get re-activated.
   // firedChannelActive = false;
   head.fireChannelInactive();
 }