pub fn session_component(id: &str) -> Option<&str>Expand description
id when it is safe as ONE path component: 1-128 bytes of
[A-Za-z0-9._-], and not . or ... Session ids
(20261029-143000-ab12) and runtime trace ids (session-<pid>-<ms>-<seq>)
both qualify; anything else is refused rather than rewritten, so two
different ids can never share a directory.