https://learn.microsoft.com/fr-fr/dotnet/api/system.runtime.serialization.formatter.writedatetime?view=netframework-4.8.1&viewFallbackFrom=net-10.0
Formatter.WriteDateTime(DateTime, String) Method (System.Runtime.Serialization) | Microsoft Learn
When overridden in a derived class, writes a DateTime value to the stream already attached to the formatter.
formatterdatetimestringmethodsystem