Enable log levels

mod foo {
  mod bar {
    pub fn run() {
      log::warn!("[bar] warn");
      log::info!("[bar] info");
      log::debug!("[bar] debug");
    }
  }
  pub fn run() {
    log::warn!("[foo] warn");
    log::info!("[foo] info");
    log::debug!("[foo] debug");
    bar::run();
  }
}
fn main() {
  env_logger::init();
  log::warn!("[root] warn");
  log::info!("[root] info");
  log::debug!("[root] debug");
  foo::run();
}