CDM 01-JUN-2022¶

- LIBRADOS_ALLOC_HINT_FLAG_DONTTRANSFORM ("hands off my data") flag
- allocated-but-unwritten extents in bluestore to be able to set bluestore_zero_block_detection=true in the field (https://tracker.ceph.com/issues/55521)
- use boost accumulators for stats collection (perf counters)
- logical large-scale testing in teuthology