An unknown field is by definition a valid SDT field, that's not known to the current version of the API.
void AddUnknownField(
string name,
IUnknownSDTField field
)| ArgumentNullException | Thrown when the input parameter is null. |
| InvalidOperationException | Thrown when the container is already closed. |
| OperationErrorException | Thrown when an error occurs. In this case ReturnCode and SDKErrorInfo are accessible from OperationErrorException and contain more information. |
| FatalErrorException | Thrown when an unrecoverable error occurs. |