It would be useful if we were able to see the current disk activity (read/write amount) on the endpoint for fetching the current state of the instance.
It’s possible, though not very likely that we’d add it as unfortunately most more kernels don’t have that information anymore (due to the I/O scheduler in use).
You can check lxc query /1.0/metrics and see if you have the metrics available there.
We do have the fields available in that API, but again, depending on whether you kernel exposes anything at all.