Shutdown process is slow, 3 seconds, even when the client is not used at all. I wonder what prevent immediate shutdown.

asyncHttpClient(
 config()
 .setConnectTimeout(5_000)
 .setRequestTimeout(20_000)
)

So I guess this is the shutdown logic:

// ChannelManager
 public void close() {
 if (allowReleaseEventLoopGroup) {
 eventLoopGroup
 .shutdownGracefully(config.getShutdownQuietPeriod(), config.getShutdownTimeout(), TimeUnit.MILLISECONDS)
 .addListener(future -> doClose());
 } else {
 doClose();
 }
 }

And I understand if I want to force faster shutdown I can pass a small value to setShutdownTimeout() builder function, but still I don't know why shutdown takes long when there was no interaction, even after close function was called.
Not sure if it is a bug or a good reason behind it.
Thanks :)