Gtk-rs async `alert` example

Cargo.toml

[package]
name = "async-ui"
version = "0.1.0"
authors = ["Dmitry Kalyanov <Kalyanov.Dmitry@gmail.com>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
futures = "0.3.4"
glib = "0.9.3"
async-std = "1.5.0"

[dependencies.gtk]
version = "0.8.1"

main.rs

pub async fn alert(title: &str, text: &str) {

    use gtk::prelude::*;
    use std::rc::Rc;
    use std::cell::RefCell;
    use futures::channel::oneshot::channel as oneshot_channel;
        
    let (result_sender, result_receiver) = oneshot_channel();
    let result_sender = Rc::new(RefCell::new(Some(result_sender)));

    let dialog = gtk::MessageDialogBuilder::new()
        .buttons(gtk::ButtonsType::Ok)
        .message_type(gtk::MessageType::Info)
        .text(text)
        .modal(true)
        .title(title)
        .type_(gtk::WindowType::Toplevel)
        .build();

    let result_sender2 = result_sender.clone();
    dialog.connect_response(move |_, response| {
        println!("Response={}", response);
        let result_sender = result_sender2.borrow_mut().take().unwrap();
        result_sender.send(()).unwrap();
    });

    dialog.show_all();

    result_receiver.await.unwrap();

    dialog.destroy();

}

async fn ui_main() {
    alert("Message", "Hello, world").await;
}

fn main() {
    gtk::init().expect("Failed to initialize Gtk+");

    glib::MainContext::default().spawn_local(async move {
        ui_main().await;
        gtk::main_quit();
    });

    gtk::main();
}