title: IllegalReferenceCountException: refCnt: 0, decrement: 1 on spring cloud gateway
body: <p>Trying to use RetryGatewayFilter programmatically. But stuck with netty IllegalReferenceCountException: refCnt: 0, decrement: 1</p>
  
  <pre><code>route("route-one", p -&gt; p
                          .readBody(String.class, i -&gt; !StringUtils.isEmpty(i)).and()
                          .path("/id")
                          .filters(f -&gt; f
                                  .modifyRequestBody(String.class, String.class, ((exchange, s) -&gt; {
                                      //Body modification
                                  }))
                                  .retry(retryConfig -&gt; {
  
                                      retryConfig.setRouteId("route-one");
  
                      RetryGatewayFilterFactory.BackoffConfig backoffConfig = new RetryGatewayFilterFactory.BackoffConfig();
                                      backoffConfig.setFirstBackoff(Duration.ofSeconds(1));
                                      backoffConfig.setMaxBackoff(Duration.ofSeconds(5));
                                      backoffConfig.setFactor(1);
                                      backoffConfig.setBasedOnPreviousValue(true);
  
                                      retryConfig.setSeries(HttpStatus.Series.SERVER_ERROR);
                                      retryConfig.setStatuses(HttpStatus.BAD_GATEWAY, HttpStatus.INTERNAL_SERVER_ERROR);
                                      retryConfig.setRetries(3);
                                      //retryConfig.setBackoff(backoffConfig);
                                  })
                          )
                          .uri(Url))
  </code></pre>
  
  <p>Same happens with GET requests too</p>