In controller I need to share some data to WebFilter (I don't want to use ServerWebExchange.getAttributes().put("KEY", "VALUE"), and my boss either), this is my current implemetation:

<code><span>@Component</span>
<span>public</span> <span>class</span> <span>RequestFilter</span> <span>implements</span> <span>WebFilter</span> {

  <span>@Override</span>
  <span>public</span> Mono&lt;Void&gt; <span>filter</span><span>(ServerWebExchange exchange, WebFilterChain chain)</span> {
    exchange.getResponse().beforeCommit(() -&gt; Mono.deferWithContext(c -&gt; {
      <span>//I CHECK WHETHER DATA SHARED FROM CONTROLLER EXIST OR NOT</span>
      System.out.println(c.hasKey(<span>"abc"</span>));
      <span>Context</span> <span>innerContext</span> <span>=</span> c.get(<span>"CONTEXT"</span>);
      System.out.println(innerContext.hasKey(<span>"abc"</span>));
      <span>return</span> Mono.empty();
    }));

    <span>ServerHttpRequest</span> <span>request</span> <span>=</span> exchange.getRequest();
    <span>BodyCaptureExchange</span> <span>bodyCaptureExchange</span> <span>=</span> <span>new</span> <span>BodyCaptureExchange</span>(exchange);

    <span>return</span> chain.filter(bodyCaptureExchange).subscriberContext(context -&gt; {
      <span>//HERE I PUT CONTEXT TO ITSELF</span>
      context = context.put(<span>"CONTEXT"</span>, context);
      <span>return</span> context;
    });
  }
}</code>

Here is my controller method:

<code><span>public</span> Mono&lt;ResponseEntity&lt;Response&gt;&gt; <span>post</span><span>(<span>@RequestBody</span> Mono&lt;Request&gt; request)</span> {
    Mono&lt;ResponseEntity&lt;Response&gt;&gt; responseEntityMono = request.flatMap(
            rq -&gt; service.requestProcess(rq).map(res -&gt; ResponseEntity.ok().body(res))
        ).subscriberContext(c -&gt; {
            <span>//HERE I GET THE INNER CONTEXT FROM ABOVE FILTER</span>
            <span>Context</span> <span>innerContext</span> <span>=</span> c.get(<span>"CONTEXT"</span>);
            <span>//PUT DATA TO IT</span>
            c = c.put(<span>"CONTEXT"</span>, innerContext.put(<span>"abc"</span>, <span>"abc"</span>));
            <span>//ALSO PUT DATA TO PARENT</span>
            c = c.put(<span>"abc"</span>, <span>"abc"</span>);
            <span>return</span> c;
        });
        
    <span>return</span> responseEntityMono;
}</code>

The System.out.println in RequestFilter print:

<code><span>false</span>
<span>false</span>
</code>

Means that data I put from controller are lost when it come to Filter.  Please correct me if I'm wrong somewhere. I really need your help Reactor version: 3.3.14 Spring boot stater webflux: 2.3.9.RELEASE