Delegate `clearFolder` to library user

[lzambarda]

Just an idea, I think

external-sort/file/file.go

Line 42 in 8a71574

err := clearFolder(chunkFolder)

is potentially dangerous.
What if the responsibility was completely offloaded to the user of the library?

[askiada]

Good point! The processing is creating chunk files. And we don't want to keep these when we are done. Also we don't want to process a potential chunk file from a previous run. I don't know what would be a better approach. Maybe to only remove files with chunk_*.csv pattern. So at least you don't remove other user files

[lzambarda]

I think that is a good alternative!
This could even be driven by a parameter or something, but prob a pattern is good enough with no extra development needed!