code: @Override
  	public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
  		return chain.filter(exchange) //
  				.subscriberContext(Context.of(SERVER_WEB_EXCHANGE, exchange));
  	}
docs: /*
  (non-Javadoc)
  @see org.springframework.web.server.WebFilter#filter(org.springframework.web.server.ServerWebExchange, org.springframework.web.server.WebFilterChain)