eql

    pub fn eql(a: BuildId, b: BuildId) bool {
        const Tag = @typeInfo(BuildId).@"union".tag_type.?;
        const a_tag: Tag = a;
        const b_tag: Tag = b;
        if (a_tag != b_tag) return false;
        return switch (a) {
            .none, .fast, .uuid, .sha1, .md5 => true,
            .hexstring => |a_hexstring| mem.eql(u8, a_hexstring.toSlice(), b.hexstring.toSlice()),
        };
    }