From the current documentation its very hard to understand what is supported in Webflux and what is not. For example Concurrent Session Control support looks to be totally missing in Webflux and should be documented and if it is supported an example on how to set it up would very much help. The examples provided are not for a reactive stack.
Comment From: rwinch
There isn't support for concurrency control in WebFlux yet. See https://github.com/spring-projects/spring-security/issues/6192