This is lightly tested on a bunch of good drives, and one cranky drive.
Sometimes I wonder why the I/O timeout is 30s and not like 3s.
We were trying to get PCI4 nvme drives and saw annoying latency issues with the hardware and (alas) software. This seems to fix it, but I have only a few miles on this code... But enough, I think in the normal path, to open it up to review.