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: threadsafe_function.rs
    path of file: ./repos/encore/runtimes/js/src
    
    the code of the file until where you have to start completion: // Fork of threadsafe_function from napi-rs that allows calling JS function manually rather than
// only returning args. This enables us to use the return value of the function.

#![allow(clippy::single_component_path_imports)]

use std::convert::Into;
use std::ffi::CString;
use std::fmt::Debug;
use std::marker::PhantomData;
use std::os::raw::c_void;
use std::ptr;
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::sync::Arc;

use napi::{check_status, sys, Env, Result, Status};
use napi::{JsError, JsFunction, NapiValue};

/// ThreadSafeFunction Context object
/// the `value` is the value passed to `call` method
pub struct ThreadSafeCallContext<T: 'static> {
    pub env: Env,
    pub value: T,
    pub callback: Option<JsFunction>,
}

#[repr(u8)]
pub enum ThreadsafeFunctionCallMode {
    NonBlocking
    
/// pub fn test_threadsafe_function(ctx: CallContext) -> Result<JsUndefined> {
///   let func = ctx.get::<JsFunction>(0)?;
///
///   let tsfn =
///       ctx
///           .env
///           .create_threadsafe_function(&func, 0, |ctx: ThreadSafeCallContext<Vec<u32>>| {
///             ctx.value
///                 .iter()
///                 .map(|v| ctx.env.create_uint32(*v))
///                 .collect::<Result<Vec<JsNumber>>>()
///           })?;
///
///   let tsfn_cloned = tsfn.clone();
///
///   thread::spawn(move || {
///       let output: Vec<u32> = vec![0, 1, 2, 3];
///       // It's okay to call a threadsafe function multiple times.
///       tsfn.call(Ok(output.clone()), ThreadsafeFunctionCallMode::Blocking);
///   });
///
///   thread::spawn(move || {
///       let output: Vec<u32> = vec![3, 2, 1, 0];
///       // It's okay to call a threadsafe function multiple times.
///       tsfn_cloned.call(Ok(output.clone()), ThreadsafeFunctionCallMode::NonBlocking);
///   });
///
///   ctx.env.get_undefined()
/// }