get_creation_date_time
Description:
Gets the creation time of the current this and returns it as a DateTime.
It is an error to call this if the FileInfo does not contain g_file_attribute_time_created. If g_file_attribute_time_created_usec is provided, the resulting DateTime will additionally have microsecond precision.
If nanosecond precision is needed, g_file_attribute_time_created_nsec must be queried separately using get_attribute_uint32.
Parameters:
| this | 
           a FileInfo.  | 
      
Returns:
| 
           creation time, or null if unknown  |