// close all channels
LOG.info("ConnectionlessBootstrap disconnecting from {}:{}", configuration.getHost(), configuration.getPort());
LOG.trace("Closing {} channels", allChannels.size());
ChannelGroupFuture future = allChannels.close();
future.awaitUninterruptibly();
// close server external resources
if (datagramChannelFactory != null) {
datagramChannelFactory.releaseExternalResources();
datagramChannelFactory = null;