pub static OPTION_REMAINING: Lazy<&'static str>
If a long option in the main group has this name, it is not treated as a
regular option. Instead it collects all non-option arguments which would
otherwise be left in
argv. The option must be of type
OPTION_REMAINING instead of simply scanning
for leftover arguments has the advantage that GOption takes care of
necessary encoding conversions for strings or filenames.