Can you put together some example csv cases that will be hard for discovery to get right? Like the sequence of data

'20120313', 'NA', 'December 4, 1955', 'Random string'

where the sequence of discovered types might be 'int', 'option[int]', 'option[date]', 'string', but at step 3, seeing that the previous integers were acceptable as dates would require tracking some more state than just the best matching type so far.