docs: public void sendStatusOnly(final HttpResponseStatus status) {
      if (!chan.isConnected()) {
        if(stats != null) {
          stats.markSendFailed();
        }
        done();
        return;
      }
  
      response.setStatus(status);
      final boolean keepalive = HttpHeaders.isKeepAlive(request);
      if (keepalive) {
        HttpHeaders.setContentLength(response, 0);
      }
      final ChannelFuture future = chan.write(response);
      if (stats != null) {
        future.addListener(new SendSuccess());
      }
      if (!keepalive) {
        future.addListener(ChannelFutureListener.CLOSE);
      }
      done();
    }