i couldn't find enough informations about howto handle DateTimeOffset and TimeSpan during serializing and deserializing with utf8json. i could find Infos about the IJsonFormatter, but not howto implement it correctly..
My example Class looks like this:
public MyClass()
{
 // This should be converted during serializing/deserializing  to Unix TimeStamp in Milliseconds  
  [JsonFormatter(typeof[CustomDateTimeConverter())]  
  public DateTimeOffSet? BeginDate { get; set; }
  // This should be converted to TotalMilliseconds
  public TimeSpan? Elapsed { get; set; } 
}
I have a function to convert the Datetime to EpochTimeStamp from this post: How to get the unix timestamp in C#
I tried to add [JsonFormatter(typeof[CustomDateTimeConverter())] to the datamember BeginDate, but need to implement it correctly..
public class CustomDateTimeConverter : IJsonFormatter
{
    public CustomDateTimeConverter()
    {
       // convert DateTime to Unix Milliseconds for Serialzing
    }
}
Or i am on the wrong way ? How can i achieve this ?
Thank you, for helping !
