*scratch*.el

pub fn connect(addr: IpAddr) -> Future<Option<TcpStreamAsync>> {
    unsafe {
        let (ret_future, ret_promise) = pair();
        rtdebug!("borrowing io to connect");
        let io = Local::unsafe_borrow::<IoFactoryObject>();
        rtdebug!("about to connect");
        let p_cell = Cell::new(ret_promise);
        (*io).tcp_connect_async(addr,
            |connect_result| {
                let ret_promise = p_cell.take();
                ret_promise.fulfill(connect_result);
            }
        );
        let f_cell = Cell::new(ret_future);
        future::from_fn(|| {
          let ret_future = f_cell.take();
          let r = ret_future.unwrap();
          match r {
              Ok(s) => Some(TcpStreamAsync::new(s)),
              Err(e) => {
                  rtdebug!("failed to async connect: %?", e);
                  io_error::cond.raise(e);
                  None
              }
          }
        })
    }
}

Is this rust? Looks like you are still using emacs. Yay! We should get together and hack some weekend.