Add a way to write the BOM that Excel likes to read the csv properly

[GregOriol]

It's maybe not the best of the best in the CSV world, but Excel likes to have a BOM at the beginning of the file to read it properly. It could be a good idea to add an option to write it, since there is already an implementation to read it.

For now, I'm using as a quick "hack" to make the CSV look good in Excel:

let csv = try CSVWriter(...codecType: UTF8.self,...)
csv.stream.write([0xef, 0xbb, 0xbf], maxLength: 3) // UnicodeBOM.utf8

[RafaelPlantard]

@GregOriol could you explain better your work-around, I'm facing the same issue?

[GregOriol]

@RafaelPlantard Not sure what you need more here :-) Create the new writer instance with the codecType as in my example, add the line to write the BOM as in my example and then write your data as usual/as described in the readme of the project.

[RafaelPlantard]

@GregOriol you write this before each line or only before the first line:
csv.stream.write([0xef, 0xbb, 0xbf], maxLength: 3) // UnicodeBOM.utf8
?

[GregOriol]

@RafaelPlantard Only once! The BOM (ie. those 3 special chars) should be at the very beginning of the file