Rust

the code I have written isn't very idiomatic or efficient. I am still new to Rust so I am learning things. I am amazed that I can write a pastebin in just 60 lines of Rust code. It's awesome. I am thinking about deploying it on my server.

any suggestions would be appreciated :)

code:

use axum::{extract::Path, routing::get, Router};
use std::fs::{read_to_string, File};
use std::io::prelude::*;
use std::net::{TcpListener, TcpStream};
use std::str;

const MAX_FILE_SIZE: usize = 1024 * 1024 * 10;
static mut FILE_COUNT: usize = 0;

fn handle_client(stream: &mut TcpStream) -> std::io::Result<()> {
    let mut buf = vec![0; 1024];
    unsafe {
        let file_name = FILE_COUNT.to_string();
        FILE_COUNT += 1;
        let mut file = File::create(file_name)?;
        let mut size: usize = 0;
        loop {
            let read_data = stream.read(&mut buf).unwrap();
            size += read_data;
            if size >= MAX_FILE_SIZE {
                return Ok(())
            }
            if read_data == 0 {
                return Ok(());
            }
            stream.write_all(&buf[..read_data]).unwrap();
            write!(file, "{}", str::from_utf8(&buf[..read_data]).unwrap())?;
        }
    }
}

async fn upload_handle() -> std::io::Result<()> {
    let listener = TcpListener::bind("127.0.0.1:8080")?;

    // accept connections and process them serially
    for stream in listener.incoming() {
        handle_client(&mut stream?)?;
    }

    Ok(())
}

async fn handle(Path(id): Path<String>) -> String {
    if let Ok(content) = read_to_string(id) {
        return content;
    }
    return String::from("ERROR: File not found");
}

#[tokio::main]
async fn main() {
    tokio::spawn(upload_handle());

    let app = Router::new()
        .route("/", get(|| async { "Paste something in pastebin!" }))
        .route("/{id}", get(handle));

    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
    axum::serve(listener, app).await.unwrap();
}