Main.rs with problem with signature of on_ws_request

main.rs

// This version compiles, and works
#[macro_use]
extern crate serde_derive;

use serde_json::{Map, Value};
use tide_websockets::{
    WebSocket,
    Message
};
use async_std::stream::StreamExt;
use std::sync::{
    Arc
};
use async_std::sync::{ 
    RwLock
};
use std::collections::HashMap;

const _DEFAULT_4XX_BODY: &[u8] = b"Oops! I can't find what you're looking for..." as &[_];
const _DEFAULT_5XX_BODY: &[u8] = b"I'm broken, apparently." as &[_];

#[derive(Deserialize, Serialize, Debug, Clone)]
struct Vote {
    uid: String,
    card: String
}

#[derive(Clone,Debug)]
struct State {
    votes: Arc<RwLock<HashMap<String,Vote>>>
}

fn start_msg() -> Map<String, Value> {
    let mut map = Map::new();
    map.insert("Bool Example".to_string(), false.into());
    map.insert("String Example".to_string(), "Str".to_string().into());    
    map.insert("Number Example".to_string(), 2.into());
    map
}

async fn on_ws_request(req : tide::Request<State>, mut stream : tide_websockets::WebSocketConnection) 
    -> std::result::Result<(), tide::Error> { 
        tide::log::info!("Got a WebSocket connection");
        stream.send_json(&start_msg()).await.unwrap();
        tide::log::info!("Sent start message");
        let mut votes = req.state().votes.write().await; 
        loop {
            for (k, v) in votes.iter() {
                tide::log::info!("{:?}: \"{:?}\"", k, v);
            }
            let raw = stream.next().await.unwrap();
            tide::log::info!("State: {:?}", req.state());
            tide::log::info!("Received raw-> {:?}\n", &raw);
            if let Ok(Message::Text(msg)) = raw {
                tide::log::info!("Received msg-> {:?}\n", &msg);
                let vote : Vote =  serde_json::from_str(&msg).unwrap();
                votes.insert(vote.uid.clone(), vote.clone());
                tide::log::info!("Received vote= {:?}", vote);
            }
        }
}

#[async_std::main]
async fn main() -> std::result::Result<(), std::io::Error> {
    tide::log::start();
    let mut app = tide::with_state( State { votes: Default::default() });
    app.at("/").serve_file("plan.html")?;
    app.at("/ws").get(WebSocket::new(on_ws_request));
    app.listen("127.0.0.1:8080").await?;
    Ok(())
}