getopt usage help to stderr?

[Richard (Rikki) Andrew Cattermole]

I think that you are almost there.

https://dlang.org/phobos/std_getopt.html#.defaultGetoptFormatter

Try using: https://dlang.org/phobos/std_stdio.html#.File.lockingTextWriter

``defaultGetoptFormatter(stderr.lockingTextWriter, "heading", 
helpInformation.options);``