A disposal-hygiene release: a disposed pool now reads as disposed.
- Utf8StringPool.Count throws ObjectDisposedException after disposal, like Intern, TryGet and
Reset, instead of reporting a cleared table as zero. - The pool's observable instruments publish no measurement once disposed, rather than a
healthy-looking zero. They are registered on a caller-supplied meter that outlives the pool, so
a disposed pool kept reporting UniqueCount=0 and TotalBytesInterned=0 indefinitely.
See CHANGELOG.md for the full list.