fix(vsock): save state after sending a notification

Implements firecracker-microvm#4812

Kick vsock during VM resume

Implements firecracker-microvm#4796

re-enable async pf

perf: remove another snapshot flush

perf: disable flush on snapshot saving

Firecracker is taking significant time on saving the snapshot file. For
comparison: writing the memory snapshot by us (1GiB) takes 1s, and
writing the snapshot file by Firecracker (150KiB) takes 8.5s. We presume
this is because of the syncing of the metadata, which is why we disable
it for now. The filesystem should still handle persisting, and given the
fact that the snapshot/memory files are temporary anyway, we can afford
to not sync/flush.

feat(balloon): enable memory reclaiming

uffd: enable non-blocking mode

Merge tag 'v1.2.1' into uffd-superbranch-3

Changed

* Upgraded Rust toolchain from 1.64.0 to 1.66.1.

Fixed

* A race condition that has been identified between the API thread and the VMM
  thread due to a misconfiguration of the `api_event_fd`.

Possible race condition between VMM thread and API thread (FC 1.2)

firecracker-microvm@174e042

Revert "add logging"

This reverts commit 017d015.