fn index(item: web::Json<item::Item>) -> HttpResponse {
    let client = reqwest::Client::new();
    let res = client.post(&url).json(&item).send();
    HttpResponse::Ok().json(item.0)
}

[...]

 HttpServer::new(|| {
        App::new()
            .wrap(middleware::Logger::default())
            .data(web::JsonConfig::default().limit(4096))
            .service(web::resource("/push").route(web::post().to(index)))
    })
    .bind("0.0.0.0:8080")?
    .run()