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: service.rs
    path of file: ./repos/linkerd2-proxy/linkerd/distribute/src
    
    the code of the file until where you have to start completion: use super::{Distribution, WeightedKeys};
use indexmap::IndexMap;
use linkerd_stack::Service;
use rand::{
    distributions::{Distribution as _, WeightedError},
    rngs::SmallRng,
    SeedableRng,
};
use std::{
    hash::Hash,
    sync::Arc,
    task::{Context, Poll},
};

/// A service that distributes requests over a set of backends.
#[derive(Debug)]
pub struct Distribute<K, S> {
    backends: IndexMap<K, S>,
    sele
    
    fn random_available_woken() {
        let (mulder, mut mulder_ctl) = mock::pair::<(), ()>();
        let (scully, mut scully_ctl) = mock::pair::<(), ()>();
        let (skinner, mut skinner_ctl) = mock::pair::<(), ()>();
        let mut dist_svc = mock::Spawn::new(Distribute::new(
            vec![("mulder", mulder), ("scully", scully), ("skinner", skinner)]
                .into_iter()
                .collect(),
            Distribution::random_available([("mulder", 1), ("scully", 99998), ("skinner", 1)])
                .unwrap(),
        ));

        mulder_ctl.allow(0);
        scully_ctl.allow(0);
        skinner_ctl.allow(0);
        assert_pending!(dist_svc.poll_ready());
        skinner_ctl.allow(1);
        assert!(dist_svc.is_woken());
    }