code: protected Promise disconnect() {
  		if (group != null) {
  			try {
  				group.shutdownGracefully(1, 1, TimeUnit.SECONDS).await(1, TimeUnit.SECONDS);
  			} catch (InterruptedException ignored) {
  			} finally {
  				group = null;
  			}
  		}
  		if (resources != null) {
  			try {
  				resources.shutdown(1, 1, TimeUnit.SECONDS).await(1, TimeUnit.SECONDS);
  			} catch (InterruptedException ignored) {
  			} finally {
  				resources = null;
  			}
  		}
  		if (acceptor != null) {
  			try {
  				acceptor.shutdownNow();
  			} catch (Exception ignored) {
  			} finally {
  				acceptor = null;
  			}
  		}
  		return Promise.resolve();
  	}
docs: --- DISCONNECT ---