Taking a snapshot became prohibitively slow because of the
migration_transferred_bytes() call in migration_rate_exceeded() [0].
This also applied to the async snapshot taking in Proxmox VE, so
work around the issue until it is fixed upstream.
[0]: https://gitlab.com/qemu-project/qemu/-/issues/1821
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>