** Creates and keeps tabs on `ThreadStash` so they may be cleaned up, say, at the end of a web ** request.** ** @since 1.3.0constmixin ThreadStashManager {** creates a stash with the given prefixabstract ThreadStash createStash(Str owner)** Returns all (fully qualified) keys associated / used with this manager abstract Str[] keys()** Removes all values associated / used with this managerabstract Void cleanUp()}