In webflux, the [http method is used as operation name](https://github.com/opentracing-contrib/java-spring-web/blob/e394c57455bd60ea05a325a1417152c0b8386f56/opentracing-spring-web/src/main/java/io/opentracing/contrib/spring/web/webfilter/TracingOperator.java#L68). Preferably, this should be the controller method name, as is already the case in non-webflux spring.