UTM 5.0.8 Apple Virtualization: disk quiescence and backing-file release after shutdown

[aethercrest]

For UTM 5.0.8's Apple Virtualization backend on macOS 26, using a macOS guest with an internal writable RAW virtio disk:

1. What supported lifecycle event guarantees that acknowledged guest flushes have completed and that no further VM or framework writes can reach the disk's backing file?
2. Is that event distinct from UTM's reported 'stopped' state?
3. Which disk synchronization mode applies to this configuration?
4. After a normal shutdown, what establishes that the storage attachment has been released and the backing-file handle closed?
5. Does the guarantee differ following a forced stop, failed stop or asynchronous cleanup?
6. Is there a documented API, callback or implementation reference that establishes when independent host-side inspection is safe?