Nolocal close

[yellowhatter]

Implement close in the way it can be safely waited and awaited in atexit

[evshary]

It still failed when I tested with the following code

use std::sync::OnceLock;
use zenoh::{Config, Session, Wait};
static SESSION: OnceLock<Session> = OnceLock::new();

fn main() {
    let s = SESSION.get_or_init(|| zenoh::open(Config::default()).wait().unwrap());
    println!("> zid: {}", s.zid());
    unsafe { libc::atexit(close_session) };
}

extern "C" fn close_session() {
    SESSION.get().unwrap().close().wait().unwrap();
}