The 0 W of shutdown and of the Stop button now waits (bounded, 2 s) for a write already on its way to the same unit, for every driver, GoodWe included. Once shutdown has begun, cycle, heartbeat and safety-stop writes are dropped right before the write is created. One shared wait (_await_inflight) serves the 0 W and SMA-10's _release_last. Co-Authored-By: Claude <noreply@anthropic.com>