Override CSV export

[sveinnetnordic]

Feature proposal

I could not find a way to override the export in the class CsvInputStreamFactory, so I had to modify the code. Hope my code will show what I mean:

Describe solution expectations

No response

Additional information

Vaadin 24.4.10, GridExporterAddon 2.3.2

[javier-godoy]

It order to support this use case we could move new CSVWriter(os) to a protected method (so that you don't have to rewrite accept just for that), and make buildRow protected too (so that you can override it), as well as making CsvStreamResourceWriter and BaseStreamResourceWriter public classes.

[sveinnetnordic]

I think that is a good solution. The only missing thing then will be:
// writer.writeNext(headers);

[javier-godoy]

Created #149 as an epic to address various refactors necessary to enable this case.