@Override public void channelClosed(ChannelHandlerContext channelHandlerContext,ChannelStateEvent channelStateEvent) throws Exception {
  curr_conns.decrementAndGet();
  channelGroup.remove(channelHandlerContext.getChannel());
}

@ Override public void channelClosed ( ChannelHandlerContext channelHandlerContext , ChannelStateEvent channelStateEvent ) throws Exception { curr_conns . decrementAndGet ( ) ; channelGroup . remove ( channelHandlerContext . getChannel ( ) ) ; }
on close we manage some statistics , and remove this connection from the channel group .
