sizeTotal

pub fn sizeTotal(self: *const HeaderResizeWidget) f32 {
        var total: f32 = switch (self.direction) {
            .vertical => scrollbar_padding_defaults.w,
            .horizontal => scrollbar_padding_defaults.h,
        };
        for (self.init_opts.sizes) |s| {
            total += s;
        }
        return total;
    }