Restore hotkeys in pane_grid example

- Implement `subscription::events_with`
- Remove `pane_grid::KeyPressEvent`
- Return closest sibling in `pane_grid::State::close`

native/src/subscription/events.rs

@@ -2,17 +2,26 @@ use crate::{
     subscription::{EventStream, Recipe},
     Event, Hasher,
 };
+use iced_futures::futures::future;
+use iced_futures::futures::StreamExt;
 use iced_futures::BoxStream;
 
-pub struct Events;
+pub struct Events<Message> {
+    pub(super) f: fn(Event) -> Option<Message>,
+}
 
-impl Recipe<Hasher, Event> for Events {
-    type Output = Event;
+impl<Message> Recipe<Hasher, Event> for Events<Message>
+where
+    Message: 'static + Send,
+{
+    type Output = Message;
 
     fn hash(&self, state: &mut Hasher) {
         use std::hash::Hash;
 
-        std::any::TypeId::of::<Self>().hash(state);
+        struct Marker;
+        std::any::TypeId::of::<Marker>().hash(state);
+        self.f.hash(state);
     }
 
     fn stream(
@@ -20,5 +29,7 @@ impl Recipe<Hasher, Event> for Events {
         event_stream: EventStream,
     ) -> BoxStream<Self::Output> {
         event_stream
+            .filter_map(move |event| future::ready((self.f)(event)))
+            .boxed()
     }
 }