Declaration
public static string ToIsoStringRoundtrip(
    this DateTime datetime,
    IsoDateFormat format = IsoDateFormat.HumanReadable,
    IsoDatePrecision minPrecision = IsoDatePrecision.Days
)Summary
            Returns a string representation of the date/time in an ISO-8601-like format. Use this if the result must be round-trippable
            without losing any information. The function will omit higher-precision parts whose values are zeroes, as permitted by the standard.
            
Parameters
| this DateTime | datetime | Date/time to convert. | 
| IsoDateFormat | format | One of the several pre-defined formats to use. | 
| IsoDatePrecision | minPrecision | Minimum precision of the resulting string. The actual precision is determined by what's available in the date/time, bounded by this parameter. |