Slows down around iteration 460000:
$ RUST_LOG=info cargo run --release
…
[2022-02-25T02:35:25Z INFO redb_debug] 46513
[2022-02-25T02:35:25Z INFO redb_debug] 46514
[2022-02-25T02:35:25Z INFO redb_debug] 46515
[2022-02-25T02:35:25Z INFO redb_debug] 46516
[2022-02-25T02:35:25Z INFO redb_debug] 46517
[2022-02-25T02:35:25Z INFO redb_debug] 46518
[2022-02-25T02:35:25Z INFO redb_debug] 46519
[2022-02-25T02:35:25Z INFO redb_debug] 46520
[2022-02-25T02:35:25Z INFO redb_debug] 46521
[2022-02-25T02:35:25Z INFO redb_debug] 46522
[2022-02-25T02:35:25Z INFO redb_debug] 46523
[2022-02-25T02:35:25Z INFO redb_debug] 46524
[2022-02-25T02:35:25Z INFO redb_debug] 46525
[2022-02-25T02:35:25Z INFO redb_debug] 46526
[2022-02-25T02:35:25Z INFO redb_debug] 46527
[2022-02-25T02:35:25Z INFO redb_debug] 46528
[2022-02-25T02:35:25Z INFO redb_debug] 46529
[2022-02-25T02:35:25Z INFO redb_debug] 46530
[2022-02-25T02:35:25Z INFO redb_debug] 46531
[2022-02-25T02:35:25Z INFO redb_debug] 46532
[2022-02-25T02:35:25Z INFO redb_debug] 46533
[2022-02-25T02:35:25Z INFO redb_debug] 46534
[2022-02-25T02:35:34Z INFO redb_debug] 46535
[2022-02-25T02:35:43Z INFO redb_debug] 46536
[2022-02-25T02:35:52Z INFO redb_debug] 46537
[2022-02-25T02:36:02Z INFO redb_debug] 46538
[2022-02-25T02:36:11Z INFO redb_debug] 46539
[2022-02-25T02:36:20Z INFO redb_debug] 46540
[2022-02-25T02:36:30Z INFO redb_debug] 46541
[2022-02-25T02:36:39Z INFO redb_debug] 46542
[2022-02-25T02:36:48Z INFO redb_debug] 46543
[2022-02-25T02:36:58Z INFO redb_debug] 46544