@GetMapping("/owners/{ownerId}/pets/{petId}")
            Flux<Integer> findPet(
                    @MatrixVariable(name = "q", pathVar = "ownerId") int q1,
                    @MatrixVariable(name = "q", pathVar = "petId") int q2) {
                return Flux.just(q1, q2);
            }
Integration test for <a href="https://docs.spring.io/spring-framework/reference/web/webflux/controller/ann-methods/matrix-variables.html">Matrix Variables</a>.
spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/MatrixVariablesTest.java