main
[space_map] Optimize zero-filling loops in Aggregator region lookup
[space_map] Replace explicit counter loops with iterator zips
[space map/allocated_blocks] pass io engine by reference
[space_map] Split SpaceMap trait into RefCount and SpaceMap
[space_map] Factor out repair_space_map
[space map] Fix incorrect index_entry.nr_free while expansion
[all] Apply cargo fmt, and fix clippy lints
[build] Update nom to 8.0.0
[build] Update rand to 0.9.1