[lgmp] core: add adaptive stream polling

Advance LGMP to the stream polling fallback implementation.

The new API combines short spins with bounded exponential backoff and
resets on observed progress. Notification callbacks remain advisory, so
plain shared-memory transports keep making progress without doorbells.
This commit is contained in:
Geoffrey McRae
2026-08-15 14:11:10 +10:00
parent a2dd4c246d
commit b353b5ef06