2023-02-04: specify min Rust version, tagged 0.4.3
2023-01-21: minor doc update, tagged 0.4.2
2023-01-15: using generic type for counters, tagged 0.4.1
2022-12-31: using revision 2021, tagged 0.2.3
2020-01-25: relaxed constraints, added len, total, max and tagged 0.2.1
2020-01-11: changed to use u64 and added merge func, tagged 0.2.0
2020-01-05: initial release, tagged 0.1.0