Save and load SRAM at all the right times

src/app.rs

@@ -1,4 +1,4 @@
-use std::{collections::HashSet, num::NonZero, sync::Arc, thread};
+use std::{collections::HashSet, num::NonZero, sync::Arc, thread, time::Duration};
 
 use egui::{
     ahash::{HashMap, HashMapExt},
@@ -15,7 +15,7 @@ use winit::{
 
 use crate::{
     controller::ControllerManager,
-    emulator::{EmulatorClient, SimId},
+    emulator::{EmulatorClient, EmulatorCommand, SimId},
     input::MappingProvider,
     window::{AppWindow, GameWindow, InputWindow},
 };
@@ -170,6 +170,15 @@ impl ApplicationHandler<UserEvent> for Application {
             viewport.window.request_redraw();
         }
     }
+
+    fn exiting(&mut self, _event_loop: &ActiveEventLoop) {
+        let (sender, receiver) = oneshot::channel();
+        if self.client.send_command(EmulatorCommand::Exit(sender)) {
+            if let Err(err) = receiver.recv_timeout(Duration::from_secs(5)) {
+                eprintln!("could not gracefully exit: {}", err);
+            }
+        }
+    }
 }
 
 struct Viewport {