You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/wezterm/window/src/os/macos
    
    the code of the file until where you have to start completion: use cocoa::base::{id, nil};
use cocoa::foundation::NSString;
use objc::rc::StrongPtr;
use objc::runtime::Object;
use objc::*;

mod app;
pub mod bitmap;
pub mod clipboard
    
unsafe fn nsstring_to_str<'a>(mut ns: *mut Object) -> &'a str {
    let is_astring: bool = msg_send![ns, isKindOfClass: class!(NSAttributedString)];
    if is_astring {
        ns = msg_send![ns, string];
    }
    let data = NSString::UTF8String(ns as id) as *const u8;
    let len = NSString::len(ns as id);
    let bytes = std::slice::from_raw_parts(data, len);
    std::str::from_utf8_unchecked(bytes)
}