[Libreoffice] How to write debug output to console or file?

Hello,

To help with debugging, it'd be very useful for me to be able to write
out variable values from within the code. Writing to the console or a
file would be fine.

std::cout doesn't work with any of the internal (unicode) string types
like OUString. Is there a way to cast them to something that cout can
deal with, or is there some logger that can write these strings to a
file?