pub fn unique_filename() -> String {
    let uuid = Uuid::new_v4().to_simple().to_string();
    let suffix = &uuid[0..2];
    format!("code-{}-{}", time::now().to_timespec().sec, suffix)
}
Return a timestamp-based filename for `dumpCode`.

The timestamp has a 2-character identifier attached to prevent naming conflicts.
weld/src/util/dump.rs