Our team wrote some code that broadly looked like this:

MDC.put("color", "red");

try(ignored = MDC.putCloseable("color", "green")) {
...
}

assertTrue(MDC.get("color", "green")) // fails, the key is deleted

It should be an easy patch to allow callers to nest putCloseable calls and get expected results; in fact, I'll go try to write one now.

Thank you very much, by the way, for SLF4j -- it's a wonderful tool. Cheers