docs: public static void sendNotModified(ChannelHandlerContext ctx) {
  		FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, NOT_MODIFIED);
  		setDateHeader(response);
  
  		// close the connection as soon as the error message is sent.
  		ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
  	}