Function gstuff::last_modified_sec

pub fn last_modified_sec(path: &dyn AsRef<Path>) -> Result<f64, String>

Last-modified of the file in seconds since the UNIX epoch, with fractions.
Returns 0 if the file does not exists.

A typical use case:

if (now_float() - try_s! (last_modified_sec (&path)) > 600.) {update (&path)}