When using DateTime{Offset}.ParseExact with a culture that employs genitive month names, the public DateTimeFormatInfo.AbbreviatedMonthGenitiveNames and DateTimeFormatInfo.MonthGenitiveNames properties are being accessed to get a string[] of the month names, but those properties clone. If we instead access the internal non-cloning version, we save on an array allocation on each parse.

private CultureInfo _ci = new CultureInfo("ru-RU");

[Benchmark] public DateTime Parse() => DateTime.ParseExact("вторник, 18 апреля 2023 04:31:26", "dddd, dd MMMM yyyy HH:mm:ss", _ci);