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: distributor.rs
    path of file: ./repos/bastion/src/bastion/src
    
    the code of the file until where you have to start completion: //! `Distributor` is a mechanism that allows you to send messages to children.

use crate::{
    message::{Answer, Message, MessageHandler},
    prelude::{ChildRef, SendError},
    system::{STRING_INTERNER, SYSTEM},
};
use anyhow::Result as AnyResult;
use futures::channel::oneshot;
use lasso::Spur;
use std::{
    fmt::Debug,
    sync::mpsc::{channel, Receiver},
};

// Copy is fine here because we're working
// with interned strings here
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
/// The `Distributor` is the main message passing mechanism we will use.
/// it provides methods that will all
    
    fn test_subscribe() {
        let temp_distributor = Distributor::named("temp distributor");

        assert!(
            temp_distributor.tell_one("hello!").is_err(),
            "should not be able to send message to an empty distributor"
        );

        let one_child: ChildRef = run!(async {
            Distributor::named(SUBSCRIBE_TEST_DISTRIBUTOR)
                .request(())
                .await
                .unwrap()
                .unwrap()
        });
        temp_distributor.subscribe(one_child.clone()).unwrap();

        temp_distributor
            .tell_one("hello!")
            .expect("should be able to send message a distributor that has a subscriber");

        temp_distributor.unsubscribe(one_child).unwrap();

        assert!(
            temp_distributor.tell_one("hello!").is_err(),
            "should not be able to send message to a distributor who's sole subscriber unsubscribed"
        );
    }