# Constants
AllowMissingSubsecond allows the value to contain only a date and time.
AllowMissingTime allows the value to contain only a date.
AllowMissingTimezone allows the value to be missing the timezone information.
AllowNumericTimezone allows the value to represent timezones in their numeric form.
AllowSpaceSeparator allows the presence of a space instead of a 'T' as separator between the date and time.
Flexible is a combination of all validation flag that allow for non-strict checking of the input value.
Strict is a validation flag used to represent a string iso8601 validation (this is the default).
# Type aliases
ValidFlags is a bitset type used to configure the behavior of the Validfunction.