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: distributed-fwrite.rs
    path of file: ./repos/bastion/src/bastion/examples
    
    the code of the file until where you have to start completion: #[cfg(not(target_os = "windows"))]
use std::fs::File;
use std::fs::OpenOptions;
#[cfg(target_os = "windows")]
use std::io::Write;
use std::path::PathBuf;
use std::sync::Arc;

#[cfg(not(target_os = "windows"))]
use futures::*;

use bastion::prelude::*;

///
/// Parallel (MapReduce) job which async writes results to a single output file
///
/// Prologue:
/// This example maps a stream of cycling values([0,1,2,3,4,0,1,2,3,4...]) one by one:
/// to 10 workers and every worker compute the double of what they receive and send back.
///
/// Then mapper aggregates the doubled values and write them in their receiving order.
///
/// Try increasing the worker count. Yes!
fn main() {
    env_logger::init();

    Bastion::init();

    // Workers that process the work.
    let workers = Bastion::children(|children: Children| {
        children
            .with_redundancy(10) // Let's have a pool of ten workers.
            .with_exec(move |ctx: BastionContext| {
                async move {
                    println!("Worker started!");

                    // Start receiving work
                    loop {
                        msg! { ctx.recv().await?,
                            msg: u64 =!> {
                                let data: u64 = msg.wrapping_mul(2);
                                println!("Child doubled the value of {} and gave {}", msg, data); // true
                                let _ = answer!(ctx, data);
                            };
                            _: _ => ();
                        }
                    }
                }
            })
    })
    .expect("Couldn't start a new children group.");

    // Get a shadowed sharable reference of workers.
    let workers = Arc::new(workers);

    // Mapper that generates work.
    Bastion::children(|children: Children| {
        children.with_exec(move |ctx: BastionContext| {
            let workers = workers.clone();
            async move {
                println!("Mapper st
    
fn main() {
    env_logger::init();

    Bastion::init();

    // Workers that process the work.
    let workers = Bastion::children(|children: Children| {
        children
            .with_redundancy(10) // Let's have a pool of ten workers.
            .with_exec(move |ctx: BastionContext| {
                async move {
                    println!("Worker started!");

                    // Start receiving work
                    loop {
                        msg! { ctx.recv().await?,
                            msg: u64 =!> {
                                let data: u64 = msg.wrapping_mul(2);
                                println!("Child doubled the value of {} and gave {}", msg, data); // true
                                let _ = answer!(ctx, data);
                            };
                            _: _ => ();
                        }
                    }
                }
            })
    })
    .expect("Couldn't start a new children group.");

    // Get a shadowed sharable reference of workers.
    let workers = Arc::new(workers);

    // Mapper that generates work.
    Bastion::children(|children: Children| {
        children.with_exec(move |ctx: BastionContext| {
            let workers = workers.clone();
            async move {
                println!("Mapper started!");

                let mut path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
                path.push("data");
                path.push("distwrite");

                if !path.exists() || !path.is_file() {
                    Bastion::stop();
                    panic!("The file could not be opened.");
                }

                let fo = OpenOptions::new()
                    .read(true)
                    .write(true)
                    .open(&path)
                    .unwrap();

                #[cfg(not(target_os = "windows"))]
                let mut file = Handle::<File>::new(fo).unwrap();
                #[cfg(target_os = "windows")]
                let mut file = fo;

                // Distribute your workload to workers
                for id_worker_pair in workers.elems().iter().enumerate() {
                    let data = cycle(id_worker_pair.0 as u64, 5);

                    let computed: Answer = ctx.ask(&id_worker_pair.1.addr(), data).unwrap();
                    msg! { computed.await?,
                        msg: u64 => {
                            // Handle the answer...
                            println!("Source received the computed value: {}", msg);
                            #[cfg(target_os = "windows")]
                            file.write_all(msg.to_string().as_bytes()).unwrap();
                            #[cfg(not(target_os = "windows"))]
                            file.write_all(msg.to_string().as_bytes()).await.unwrap();
                        };
                        _: _ => ();
                    }
                }

                // Send a signal to system that computation is finished.
                Bastion::stop();

                Ok(())
            }
        })
    })
    .expect("Couldn't start a new children group.");

    Bastion::start();
    Bastion::block_until_stopped();
}