- the sync.Pool default uses little memory under CI.
- arena approach provides ability to control the maximum memory
used by rbf Cursors.
- cursor caching is adjustable with --rbf-cursor-cache
currently 0 by default (meaning use sync.Pool), and
larger than 0 meaning use an arena of this size.
With the arena, 20 or less is needed to pass CI.
- rbf test suite runs ~ 4x faster
- kitchen sink ingest test runs 16% faster.
- report TotalAlloc in CALLSTATs
fixes#1105
- fix a bug in computing leafCell.BitN in a run after a bit Remove
- shrink bitmaps on remove
- util_test.go has Cursor.DebugSlowCheckAllPages to verify;
used by cursor_test.go
