use std::fs;use std::path::Path;fn main() {    let samples_dir = Path::new("src/assets/samples");    if !samples_dir.exists() {        return;    }    println!("cargo:rerun-if-changed={}", samples_dir.display());    visit_dir(samples_dir);}fn visit_dir(dir: &Path) {    let entries = match fs::read_dir(dir) {        Ok(entries) => entries,        Err(_) => return,    };    for entry in entries.flatten() {        let path = entry.path();        println!("cargo:rerun-if-changed={}", path.display());        if path.is_dir() {            visit_dir(&path);        }    }}