+ Unregistration will fail, if the vhost queue has in-flight
+ packets that are not completed.
+
+ Unregister async copy devices in vring_state_changed() may
+ fail, as this API tries to acquire the spinlock of vhost
+ queue. The recommended way is to unregister async copy
+ devices for all vhost queues in destroy_device(), when a
+ virtio device is paused or shut down.
+
+* ``rte_vhost_async_channel_unregister_thread_unsafe(vid, queue_id)``
+
+ Unregister the async copy device channel for a vhost queue without
+ performing any locking.
+
+ This function is only safe to call in vhost callback functions
+ (i.e., struct vhost_device_ops).