private void closeMainChannel() {
        if (this.mainChannel != null) {
            Log.info("Closing channel {}", mainChannel);
            mainChannel.close();
        }
    }
Close the main channel (this is not synchronous and does not verify the channel has closed).
xmppserver/src/main/java/org/jivesoftware/openfire/spi/NettyConnectionAcceptor.java